Test Bank for Conceptual Physical Science, 6th Edition

Conceptual Physical Science, 6e (Hewitt) Chapter 2 Newton’s Laws of Motion 2.1 Newton’s First Law of Motion 1) Inertia is defined as a A) force. B) property of matter. C) change in motion. D) none of the above Answer: B Diff: 1 Topic: Newton’s First Law of Motion 2) If you carry a heavy bag of groceries and bang your hand against the wall, the concept that best explains why your hand hurts is A) inertia. B) gravity. C) resistance. D) none of the above Answer: A Diff: 1 Topic: Newton’s First Law of Motion 3) A quick jerk on a sheet of paper beneath a box of cereal doesn’t topple the box, which best illustrates that A) the box has no acceleration. B) there is an action-reaction pair of forces. C) gravity tends to hold the box secure. D) the box has inertia. Answer: D Diff: 1 Topic: Newton’s First Law of Motion 4) When dishes remain on a table when you yank the tablecloth beneath them, you’re demonstrating A) friction. B) inertia. C) constant motion. D) ΣF = 0. Answer: B Diff: 1 Topic: Newton’s First Law of Motion 1 Copyright © 2017 Pearson Education, Inc. 5) An object in motion tends to remain in motion A) because of a force within the object. B) only when an external force acts on it. C) without the need of a force. D) due to its nature. Answer: C Diff: 2 Topic: Newton’s First Law of Motion 6) A space probe in remote outer space continues moving A) because some kind of force acts on it. B) in a curved path. C) even though no force acts on it. D) due to gravity. Answer: C Diff: 1 Topic: Newton’s First Law of Motion 7) The force required to maintain an object at a constant velocity in free space is equal to A) zero. B) the mass of the object. C) the weight of the object. D) the force required to stop it. Answer: A Diff: 2 Topic: Newton’s Second Law of Motion 8) Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the rock tends at first to A) continue in a circular path. B) follow a straight-line path. C) spiral inward. D) fall straight downward. Answer: B Diff: 1 Topic: Newton’s First Law of Motion 9) If gravity between the Sun and Earth suddenly vanished, Earth would move in A) a curved path. B) an outward spiral path. C) an inward spiral path. D) a straight-line path. Answer: D Diff: 1 Topic: Newton’s First Law of Motion 2 Copyright © 2017 Pearson Education, Inc. 10) A ball rests in the middle of a cart. When you quickly jerk the cart forward, the ball A) hits the front of the cart. B) hits the back of the cart. C) remains in the middle of the cart. D) all, depending on how quickly the cart is pulled Answer: B Diff: 2 Topic: Newton’s First Law of Motion 11) When you step off a bus moving at 2 m/s, your horizontal speed when you meet the ground is A) zero. B) less than 2 m/s but greater than zero. C) about 2 m/s. D) greater than 2 m/s. Answer: C Diff: 2 Topic: Newton’s First Law of Motion 12) If a non-rotating object has no acceleration, then we can say for certain that it is A) at rest. B) moving at constant non-zero velocity. C) in mechanical equilibrium. D) all of the above E) none of the above Answer: C Diff: 2 Topic: Newton’s First Law of Motion 13) A hockey puck slides across a frozen pond. If ice friction and air resistance are neglected, the force needed to keep the puck sliding at constant velocity is A) 0 N. B) equal to the weight of the puck. C) the weight of the puck divided by the mass of the puck. D) the mass of the puck multiplied by 10 m/s2. E) none of the above Answer: A Diff: 2 Topic: Newton’s First Law of Motion 3 Copyright © 2017 Pearson Education, Inc. 14) The net force on any object moving at constant velocity is A) zero. B) 10 meters per second squared. C) equal to its weight. D) about half its weight. Answer: A Diff: 2 Topic: Newton’s First Law of Motion 15) A moving van with a stone lightly glued to the midpoint of its ceiling smoothly moves at constant velocity. When the glue gives way, the stone falls and hits the floor A) ahead of the midpoint of the ceiling. B) exactly below the midpoint of the ceiling. C) behind the midpoint of the ceiling. D) none of the above Answer: B Diff: 2 Topic: Newton’s First Law of Motion 16) If your automobile runs out of fuel while driving, the engine stops. You don’t come to an abrupt stop because of A) inertia. B) gravity. C) resistance. D) the principle of continuation. Answer: A Diff: 2 Topic: Newton’s First Law of Motion 17) When a rocket ship gaining speed in remote, gravity-free outer space runs out of fuel, it A) gains speed for a short time, then slows down to a constant velocity. B) gains speed for a short time, slows down, and eventually stops. C) no longer gains speed. D) comes to a quick stop. Answer: C Diff: 2 Topic: Newton’s First Law of Motion 4 Copyright © 2017 Pearson Education, Inc. 18) A bird sitting on the limb of a tree is moving about 30 km/s with respect to the Sun. If the bird takes 1 second to drop down to a worm below, the worm would be 30 km downrange from the bird when it reached the ground. This faulty reasoning is best countered with Newton’s A) law of inertia. B) law of gravity. C) laws of motion. D) none of the above Answer: A Diff: 2 Topic: Newton’s First Law of Motion 19) Earth moves about 30 km/s relative to the Sun. When you jump upward in front of a wall, the wall doesn’t slam into you at 30 km/s because the wall A) has too little gravity to influence you. B) moves in the opposite direction to you. C) and you move at the same horizontal speed, before, during, and after your jump. D) has negligible inertia compared with the Sun. Answer: C Diff: 2 Topic: Newton’s First Law of Motion 20) You’re in a fast-moving train traveling at constant velocity. If you jump straight up you land A) slightly ahead of your original position. B) at your original position. C) slightly behind your original position. Answer: B Diff: 2 Topic: Newton’s First Law of Motion 21) If you jump straight up while inside a fast-moving train that gains speed, you land A) slightly ahead of your original position. B) at your original position. C) slightly behind your original position. Answer: C Diff: 3 Topic: Newton’s First Law of Motion 22) If you jump vertically while inside a fast-moving train that is slowing down, you land A) a bit ahead of your original position. B) at your original position. C) a bit behind your original position. Answer: A Diff: 3 Topic: Newton’s First Law of Motion 5 Copyright © 2017 Pearson Education, Inc. 2.2 Newton’s Second Law of Motion 1) Newton’s second law focuses on A) speed. B) velocity. C) acceleration. D) none of the above Answer: C Diff: 1 Topic: Newton’s Second Law of Motion 2) While a car travels around a circular track at constant speed, its A) acceleration is zero. B) velocity is zero. C) both of these D) none of the above Answer: D Diff: 2 Topic: Newton’s Second Law of Motion 3) To steadily (constantly) increase the velocity of something requires a A) steadily increasing force. B) constant net force. C) decreasing force. D) none of the above Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 4) A constant net force on a railroad car produces constant A) velocity. B) acceleration. C) both of these D) neither of these Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 5) If the mass of an object does not change, a constant net force on the object produces constant A) velocity. B) acceleration. C) both of these D) none of the above Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 6 Copyright © 2017 Pearson Education, Inc. 6) A given net force propels an object along a straight-line path. If the net force were doubled, its acceleration would A) quadruple. B) double. C) stay the same. D) be half. E) none of the above Answer: B Diff: 1 Topic: Newton’s Second Law of Motion 7) If an object’s mass decreases while a constant force acts on it, the acceleration A) decreases. B) remains the same. C) increases. D) will be zero. Answer: C Diff: 1 Topic: Newton’s Second Law of Motion 8) A given net force propels an object along a straight-line path. If the mass were doubled, its acceleration would A) quadruple. B) double. C) stay the same. D) be half. E) none of the above Answer: D Diff: 1 Topic: Newton’s Second Law of Motion 9) A push on a 1-kg brick accelerates the brick. Neglecting friction, to equally accelerate a 10-kg brick requires the force to be A) just as much. B) 10 times as much. C) 100 times as much. D) one-tenth as much. E) none of the above Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 7 Copyright © 2017 Pearson Education, Inc. 10) A 10-kg block is pushed across a friction-free horizontal surface with a horizontal force of 20 N. The acceleration of the block is A) 1 m/s2. B) 2 m/s2. C) 5 m/s2. D) 10 m/s2. E) none of the above Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 11) A 10-N block and a 1-N block lie on a horizontal frictionless table. To push them with equal acceleration, we would have to push with A) equal forces on each block. B) 10 times as much force on the heavier block. C) 10 squared or 100 times as much force on the heavier block. D) one-tenth as much force on the heavier block. E) none of the above Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 12) Which object has zero acceleration? A) one at rest B) one moving at constant velocity C) one in mechanical equilibrium D) all of the above E) none of the above Answer: D Diff: 2 Topic: Newton’s Second Law of Motion 13) When an apple that weighs 1 N is held at rest above your head, the net force on the apple is A) 0 N. B) 0.1 N. C) 1 N. D) 10 N. E) none of the above Answer: A Diff: 1 Topic: Newton’s Second Law of Motion 8 Copyright © 2017 Pearson Education, Inc. 14) When an apple that weighs 1 N is dropped and freely falls, the net force on the apple is A) 0 N. B) 0.1 N. C) 1 N. D) 10 N. E) none of the above Answer: C Diff: 1 Topic: Newton’s Second Law of Motion 15) A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is A) the same as the force on the 1-kg book. B) 5 times as much as the force on the 1-kg book. C) 10 times as much as the force on the 1-kg book. D) zero. Answer: C Diff: 2 Topic: Newton’s Second Law of Motion 16) A 10-kg brick and a 1-kg book are dropped in a vacuum. The acceleration of the 10-kg brick is A) the same as that of the 1-kg book. B) 5 times as much as for the 1-kg book. C) 10 times as much as for the 1-kg book. D) zero. Answer: A Diff: 2 Topic: Newton’s Second Law of Motion 17) A heavy object and a light object in a vacuum are dropped at the same time from rest. The heavy object reaches the ground A) sooner than the light object. B) at the same time as the light object. C) later than the light object. Answer: B Diff: 1 Topic: Newton’s Second Law of Motion 9 Copyright © 2017 Pearson Education, Inc. 18) A heavy rock and a light rock in free fall have the same acceleration because the A) force due to gravity is the same on each. B) air resistance is always zero in free fall. C) inertia of each is the same. D) ratio of force to mass is the same. E) none of the above Answer: D Diff: 3 Topic: Newton’s Second Law of Motion 19) A force of 1 N accelerates a 1-kg mass at 1 m/s2. The acceleration of a 2-kg mass acted upon by a force of 2 N is A) half as much. B) twice as much. C) the same. D) none of the above Answer: C Diff: 2 Topic: Newton’s Second Law of Motion 20) Lillian pulls on a 10-kg wagon with a constant force of 30 N. What is the wagon’s acceleration? A) 0.3 m/s2 B) 3.0 m/s2 C) 10 m/s2 D) 30 m/s2 E) 300 m/s2 Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 21) Jake pulls on a 25-kg cart with a constant force of 50 N. What is the wagon’s acceleration? A) 0.2 m/s2 B) 2.0 m/s2 C) 5 m/s2 D) 20 m/s2 E) 200 m/s2 Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 10 Copyright © 2017 Pearson Education, Inc. 22) A block is dragged at constant velocity across a level surface by a force of 6 N. What is the force of friction between the block and the surface? A) less than 6 N B) more than 6 N C) 6 N D) not enough information Answer: C Diff: 2 Topic: Newton’s Second Law of Motion 23) A commercial jet has a mass of 5000 kg. During takeoff the thrust of its engine is 10,000 N, producing an acceleration of A) 0.5 m/s2. B) 1 m/s2. C) 2 m/s2. D) 4 m/s2. E) none of the above Answer: C Diff: 2 Topic: Newton’s Second Law of Motion 24) A jumbo jet of mass 100,000 kg during takeoff experience a thrust for each of its four engines of 50,000 N, producing an acceleration of A) 0.5 m/s2. B) 1 m/s2. C) 2 m/s2. D) 4 m/s2. E) none of the above Answer: C Diff: 3 Topic: Newton’s Second Law of Motion 25) A particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction. The particle with both forces acting A) is brought to a rapid halt. B) decelerates gradually to a halt. C) continues at the same speed it had before encountering the second force. D) theoretically tends to accelerate toward the speed of light. E) none of the above Answer: C Diff: 3 Topic: Newton’s Second Law of Motion 11 Copyright © 2017 Pearson Education, Inc. 26) A 10-kg block is pushed across a horizontal surface with a horizontal force of 20 N against a friction force of 10 N. The acceleration of the block is A) 1 m/s2. B) 2 m/s2. C) 5 m/s2. D) 10 m/s2. E) none of the above Answer: A Diff: 3 Topic: Newton’s Second Law of Motion 27) A 10-kg block is pushed across a horizontal surface with a horizontal force of 30 N against a friction force of 10 N. The acceleration of the block is A) 1 m/s2. B) 2 m/s2. C) 5 m/s2. D) 10 m/s2. E) none of the above Answer: B Diff: 3 Topic: Newton’s Second Law of Motion 28) A car by itself is capable of a certain maximum acceleration. When it tows a car of the same mass, its maximum acceleration is A) half. B) one-third. C) one-fourth. D) the same. E) none of these Answer: A Diff: 2 Topic: Newton’s Second Law of Motion 29) A car by itself is capable of a certain maximum acceleration. When it tows a twice-asmassive car, its maximum acceleration is A) one-half. B) one-third. C) one-fourth. D) the same. E) none of these Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 12 Copyright © 2017 Pearson Education, Inc. 30) A 1000-kg car accelerates at 2 m/s2. What is the net force exerted on the car? A) 500 N B) 1000 N C) 1500 N D) 2000 N E) none of these Answer: D Diff: 2 Topic: Newton’s Second Law of Motion 31) A tow truck exerts a force of 3000 N on a car that accelerates at 2 m/s2. What is the mass of the car? A) 500 kg B) 1000 kg C) 1500 kg D) 3000 kg E) none of these Answer: C Diff: 2 Topic: Newton’s Second Law of Motion 32) If an object’s mass is decreasing while a constant force is applied to the object, the acceleration A) decreases. B) increases. C) remains the same. Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 33) If the mass of a cart is quickly loaded to have twice the mass while a propelling force remains constant, the cart’s acceleration A) quadruples. B) doubles. C) stays the same. D) halves. E) none of these Answer: D Diff: 1 Topic: Newton’s Second Law of Motion 13 Copyright © 2017 Pearson Education, Inc. 34) You drive your car along the highway at a constant 60 km/h and apply the brakes until the car slows to 40 km/h. If at that moment you suddenly release the brakes, the car tends to A) momentarily regain its higher initial speed. B) continue moving at 40 km/h. C) decrease in speed if no other forces act. Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 35) A heavy block at rest is suspended by a vertical rope. When the block is raised at constant velocity, the rope tension A) is less than its weight. B) equals its weight. C) is greater than its weight. Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 36) A heavy block at rest is suspended by a vertical rope. When the block is accelerated upward by the rope, the rope tension A) is less than its weight. B) equals its weight. C) is greater than its weight. Answer: C Diff: 2 Topic: Newton’s Second Law of Motion 37) An huge bear and a leaf fall from a tree through the air to the ground below. The force of air resistance is greater on the A) bear. B) leaf. C) same on each Answer: A Diff: 2 Topic: Newton’s Second Law of Motion 38) After a ball tossed upward leaves your hand, the force of gravity on it A) no longer acts. B) gradually diminishes. C) gradually increases. D) remains constant. E) changes direction. Answer: D Diff: 2 Topic: Newton’s Second Law of Motion 14 Copyright © 2017 Pearson Education, Inc. 39) When you toss a ball upward, after the ball leaves your hand A) the force of your hand moves it up and gradually changes direction. B) the upward force changes direction at the top of the path. C) we see that force and velocity are essentially the same thing. D) none of the above Answer: D Diff: 3 Topic: Newton’s Second Law of Motion 40) If you are learning to juggle it would be good to slow the ball’s acceleration. You can do this by using A) lighter balls. B) heavier balls. C) more balls. D) none of the above Answer: D Diff: 2 Topic: Newton’s Second Law of Motion 41) A ball is thrown upward and caught when it returns. When air resistance affects the ball, compared with the initial upward speed, the speed of the ball when caught is A) less. B) the same. C) more. Answer: A Diff: 2 Topic: Newton’s Second Law of Motion 42) A ball tossed vertically upward reaches its highest point and then falls back to its starting point. During this up-and-down motion the acceleration of the ball is always A) in the direction of motion. B) opposite its velocity. C) directed upward. D) directed downward. Answer: D Diff: 2 Topic: Newton’s Second Law of Motion 43) How many forces act on an upwardly tossed coin when it gets to the top of its path? A) one; the force due to gravity B) two; gravity and the force in the coin itself C) three; gravity, the coin’s internal force, and a turnaround force D) none of the above Answer: A Diff: 2 Topic: Newton’s Second Law of Motion 15 Copyright © 2017 Pearson Education, Inc. 44) When you toss a coin straight up, it moves upward, turns around, and drops. During all this time the acceleration of the coin is A) upward and constant. B) downward and constant. C) first decreasing, then increasing. D) zero throughout its up and down motion. Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 45) A ball is thrown vertically into the air. Because of air resistance, its time coming down compared with its time going up is A) less. B) the same. C) more. Answer: C Diff: 2 Topic: Newton’s Second Law of Motion 46) A ball is thrown vertically upward. At the top of its vertical path, its velocity is A) 0 m/s. B) 10 m/s. C) between 0 m/s and 10 m/s. D) greater than 10 m/s. E) none of the above Answer: A Diff: 2 Topic: Newton’s Second Law of Motion 47) A stone is thrown vertically upward. At the top of its vertical path the force acting on it is A) zero. B) only the force due to gravity. C) due to air resistance. D) both due to gravity and air resistance. Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 48) A stone is thrown vertically upward. At the top of its vertical path its acceleration is A) zero. B) 10 m/s2. C) somewhat less than 10 m/s2. D) undetermined. Answer: B Diff: 3 Topic: Newton’s Second Law of Motion 16 Copyright © 2017 Pearson Education, Inc. 49) When a rock thrown straight up reaches the exact top of its path, its velocity is A) zero and its acceleration is zero. B) zero and its acceleration is 10 m/s2. C) about 10 m/s and its acceleration is zero. D) about 10 m/s and its acceleration is 10 m/s2. Answer: B Diff: 3 Topic: Newton’s Second Law of Motion 50) If an object falls with constant acceleration, the velocity of the object must A) be constant also. B) continually change by the same amount each second. C) continually change by varying amounts, depending on its speed. D) continually decrease. E) none of the above Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 51) A 1-kg ball is thrown straight up at 10 m/s. Neglecting air resistance, the net force that acts on the ball when it is halfway to the top of its path is A) 1/2 N. B) 1 N. C) 5 N. D) 7.5 N. E) 10 N. Answer: E Diff: 3 Topic: Newton’s Second Law of Motion 52) When a 500-N parachutist opens his chute and experiences 800 N of air resistance, the net force on him is A) 300 N downward. B) 500 N downward. C) 800 N downward. D) 300 N upward. E) 500 N upward. Answer: D Diff: 3 Topic: Newton’s Second Law of Motion 17 Copyright © 2017 Pearson Education, Inc. 53) When an object falls through the air, as velocity increases the net force A) increases. B) decreases. C) remains the same whether in air or in a vacuum. Answer: B Diff: 3 Topic: Newton’s Second Law of Motion 54) The air resistance of falling is greatly affected by an object’s frontal area and A) mass. B) weight. C) speed. Answer: C Diff: 2 Topic: Newton’s Second Law of Motion 55) When a falling object has reached its terminal velocity, its acceleration is A) constant. B) zero. C) g. Answer: B Diff: 1 Topic: Newton’s Second Law of Motion 56) A falling object that has reached its terminal speed continues to gain A) acceleration. B) speed. C) both of these D) none of the above Answer: D Diff: 2 Topic: Newton’s Second Law of Motion 57) The acceleration of a rocket increases as it travels upward from the ground mainly because A) gravity becomes weaker with increased distance. B) the applied force on the rocket increases as fuel is burned. C) the mass of the rocket decreases as fuel is burned. Answer: C Diff: 3 Topic: Newton’s Second Law of Motion 18 Copyright © 2017 Pearson Education, Inc. 58) An iron ball and a wooden ball of the same size are dropped from a tall tower. Taking air resistance into consideration, the object to hit the ground first will be the A) lighter wooden ball. B) heavier iron ball. C) both hit at the same time. D) not enough information Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 59) A light woman and a heavy man jump from an airplane at the same time and open their same—size parachutes at the same time. Which person reaches a state of zero acceleration first? A) the light woman B) the heavy man C) both at the same time D) not enough information Answer: A Diff: 2 Topic: Newton’s Second Law of Motion 60) A big and a small person wish to parachute at equal terminal velocities. The big person should A) jump first. B) jump lightly. C) pull upward on the supporting strands to decrease the downward net force. D) get a larger parachute. E) none of the above Answer: D Diff: 2 Topic: Newton’s Second Law of Motion 61) A skydiver who weighs 500 N reaches terminal velocity at 90 km/h. The air resistance on the skydiver is A) 90 N. B) 250 N. C) 410 N. D) 500 N. E) none of the above Answer: D Diff: 2 Topic: Newton’s Second Law of Motion 19 Copyright © 2017 Pearson Education, Inc. 62) A sack of potatoes weighing 200 N falls from an airplane. As the velocity of fall increases, air resistance also increases. When air resistance equals 200 N, the sack’s acceleration is A) 0 m/s2. B) 5 m/s2. C) 10 m/s2. D) infinite. E) none of the above Answer: A Diff: 2 Topic: Newton’s Second Law of Motion 63) A skydiver jumps from a high-flying plane. As her velocity of fall increases, her acceleration A) increases. B) decreases. C) remains unchanged regardless of air resistance. Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 64) A parachutist steps from a hovering helicopter and falls for 5 s before reaching terminal velocity. During this 5-s interval, her acceleration A) is constant. B) increases. C) decreases. D) is zero. E) none of the above Answer: C Diff: 2 Topic: Newton’s Second Law of Motion 65) If you drop an object, it will accelerate downward at a rate of 10 m/s2. If you instead throw it downward, its acceleration (in the absence of air resistance will be A) less than 10 m/s2. B) 10 m/s2. C) greater than 10 m/s2. Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 20 Copyright © 2017 Pearson Education, Inc. 66) As drops fall from a leaky faucet they become A) closer together as they fall. B) farther apart as they fall. C) a fixed distance apart as they fall. D) none of the above Answer: B Diff: 2 Topic: Newton’s Second Law of Motion 67) A pair of tennis balls fall through the air from a tall building. One ball is regular and the other is filled with lead pellets. The ball to reach the ground first is the A) regular ball. B) lead-filled ball. C) same for both Answer: B Diff: 3 Topic: Newton’s Second Law of Motion 68) A pair of tennis balls fall through the air from a tall building. One ball is regular and the other is filled with lead pellets. Air resistance just before they hit is greater for the A) regular ball. B) lead-filled ball. C) same for both Answer: B Diff: 3 Topic: Newton’s Second Law of Motion 69) What applied horizontal force will accelerate a 400-kg crate at 1 m/s2 across a factory floor against a friction force half its weight? A) 600 N B) 1600 N C) 2000 N D) 2400 N E) none of the above Answer: D Diff: 3 Topic: Newton’s Second Law of Motion 21 Copyright © 2017 Pearson Education, Inc. 70) A math book and a science book are tied together with a length of string. With the string taut, one book is pushed off the edge of a table. As it falls, the other book is dragged horizontally across the table surface. With no friction, acceleration of the books is A) zero. B) g/2. C) g. D) between zero and g. E) greater than g. Answer: D Diff: 3 Topic: Newton’s Second Law of Motion 2.3 Forces and Interactions 1) To say there is no such thing as only one force means A) there must also be an oppositely directed force. B) other forces, perhaps not evident, are there. C) gibberish. Answer: A Diff: 1 Topic: Forces and Interactions 2) You cannot exert a force on a wall A) if the wall resists. B) unless you put your mind to it. C) unless the wall simultaneously exerts the same amount of force on you. Answer: C Diff: 1 Topic: Forces and Interactions 3) When you rub your hands together, you A) can push harder on one hand than the other. B) cannot push harder on one hand than the other. C) need more information Answer: B Diff: 1 Topic: Forces and Interactions 4) Action and reaction forces are parts of A) a single interaction. B) a pair of interactions. C) multiple interactions. Answer: A Diff: 1 Topic: Forces and Interactions 22 Copyright © 2017 Pearson Education, Inc. 5) A player hits a ball with a bat. If one part of the interaction is the bat against the ball, the other part is the A) air resistance on the ball. B) weight of the ball. C) ball against the bat. D) grip of the player’s hand against the ball. E) none of the above Answer: C Diff: 2 Topic: Forces and Interactions 6) Earth exerts a force on the Moon. These two bodies make up A) one interaction. B) two interactions. C) multiple interactions. Answer: A Diff: 2 Topic: Forces and Interactions 7) A martial arts person breaks a board with a blow of 3000 N. The force that acts on the hand is A) less than 3000 N. B) 3000 N. C) more than 3000 N. D) not enough information Answer: B Diff: 3 Topic: Forces and Interactions 8) When a baseball player hits a ball with a force of 1000 N, the ball exerts a force on the bat of A) less than 1000 N. B) more than 1000 N. C) 1000 N. Answer: C Diff: 1 Topic: Forces and Interactions 9) A car traveling at 100 km/h strikes an unfortunate bug that splatters on the windshield. The force of impact is greater on the A) bug. B) car. C) same for both Answer: C Diff: 2 Topic: Forces and Interactions 23 Copyright © 2017 Pearson Education, Inc. 2.4 Newton’s Third Law of Motion 1) The emphasis of the orange-and-apple sequence in your text is A) to define systems. B) that actions equal reactions. C) that forces produce accelerations. D) defining friction as a force. E) that mass is not a force. Answer: A Diff: 1 Topic: Newton’s Third Law of Motion 2) An archer shoots an arrow. If the action force is the bowstring on the arrow, the reaction is the A) weight of the arrow. B) air resistance on the bow. C) friction of the ground on the archer’s feet. D) grip of the archer’s hand on the bow. E) arrow’s push on the bowstring. Answer: E Diff: 1 Topic: Newton’s Third Law of Motion 3) A player catches a ball. Consider the action force to be the ball against the player’s glove. The reaction is the A) player’s grip on the glove. B) force of the glove on the ball. C) friction of the ground against the player’s shoes. D) muscular effort in the player’s arms. E) none of the above Answer: B Diff: 1 Topic: Newton’s Third Law of Motion 4) Joshua is attracted toward Earth by a 500-N gravitational force. The Earth is attracted toward Joshua with a force of A) zero. B) 250 N. C) 500 N. D) 1000 N. E) none of the above Answer: C Diff: 1 Topic: Newton’s Third Law of Motion 24 Copyright © 2017 Pearson Education, Inc. 5) For a falling ball the action force is the pull of Earth on the ball. The reaction force is the A) air resistance acting against the ball. B) acceleration of the ball. C) pull of the ball on Earth. D) nonexistent. E) none of the above Answer: C Diff: 2 Topic: Newton’s Third Law of Motion 6) Earth pulls on the Moon. Similarly the Moon pulls on Earth, evidence that A) Earth and Moon pull on each other. B) Earth’s and Moon’s pulls comprise an action-reaction pair. C) both of the above D) none of the above Answer: C Diff: 2 Topic: Newton’s Third Law of Motion 7) The attraction of a person’s body toward Earth is called weight. The reaction to this force is A) the person’s body pushing against Earth’s surface. B) Earth’s surface pushing against the person’s body. C) the person’s body pulling on Earth. D) none of the above Answer: C Diff: 2 Topic: Newton’s Third Law of Motion 8) The attraction of Earth on a skydiver pulls the diver downward. The reaction to this force is A) air resistance the skydiver encounters while falling. B) Earth pulling upward on the skydiver. C) the attraction to the planets, stars, and every particle in the universe. D) all of the above E) none of the above Answer: E Diff: 3 Topic: Newton’s Third Law of Motion 9) Action and reaction pairs of forces always act on A) the same body. B) different bodies. C) either of these D) none of the above Answer: B Diff: 2 Topic: Newton’s Third Law of Motion 25 Copyright © 2017 Pearson Education, Inc. 10) A vase sits at rest on a table. If the action force is Earth pulling downward on the vase, the reaction force is the A) table pushing upward on the vase. B) vase pulling upward on Earth. C) vase pulling upward on both the table and Earth. D) none of the above Answer: B Diff: 2 Topic: Newton’s Third Law of Motion 11) Nellie whirls a tether ball in a horizontal circular path over her head. If the action force is Nellie pulling on the string, the reaction force is A) Nellie pulling on the string. B) the string pulling on Nellie. C) the ball pulling on the string. D) none of the above Answer: B Diff: 2 Topic: Newton’s Third Law of Motion 12) A Mack truck and a Mini Cooper traveling at the same speed collide head-on. The collision force is greatest on the A) Mini Cooper. B) Mack truck. C) same on both Answer: C Diff: 2 Topic: Newton’s Third Law of Motion 13) A Mack truck and a Mini Cooper traveling at the same speed collide head-on. The vehicle to undergo the greatest change in velocity will be the A) Mini Cooper. B) Mack truck. C) same Answer: A Diff: 2 Topic: Newton’s Third Law of Motion 26 Copyright © 2017 Pearson Education, Inc. 14) The force exerted on the tires of a car to directly accelerate the car along a road is exerted by the A) engine. B) tires. C) air. D) road. E) none of the above Answer: D Diff: 2 Topic: Newton’s Third Law of Motion 15) Arnold Strongman and Suzie Small each pull on opposite ends of a rope in a tug-of-war. The greater force on the rope is exerted by A) Arnold. B) Suzie. C) same by each Answer: C Diff: 2 Topic: Newton’s Third Law of Motion 16) Arnold Strongman wearing socks and Suzie Small in gym shoes have a tug-of-war on a polished floor. The likely winner is A) Arnold. B) Suzie. C) neither, a tied score D) no basis for predicting Answer: B Diff: 3 Topic: Newton’s Third Law of Motion 17) Both ends of a piece of rope are pulled by two people in a tug-of-war. If each pulls with a 400-N force, the tension in the rope is A) 0 N. B) 400 N. C) 600 N. D) 800 N. E) none of the above Answer: B Diff: 3 Topic: Newton’s Third Law of Motion 27 Copyright © 2017 Pearson Education, Inc. 18) Two people, one twice as massive as the other, attempt a tug-of-war with 12 m of rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of A) 3 m. B) 4 m. C) 5 m. D) 6 m. Answer: B Diff: 3 Topic: Newton’s Third Law of Motion 19) A friend says that the heavyweight champion of the world cannot exert a force of 50 N on a piece of tissue paper with his best punch. The tissue paper is held in midair, no tricks. You A) agree that it can’t be done. B) have reservations about this assertion. C) disagree, for a good punch easily delivers this much force. Answer: A Diff: 2 Topic: Newton’s Third Law of Motion 20) The force of a boxer’s punch is greater when it hits a A) small punching bag. B) heavy punching bag. C) both forces would be the same for the same effort Answer: B Diff: 3 Topic: Newton’s Third Law of Motion Written-Response Questions 1) If you drop a pencil while riding on a smooth riding bus, why does the pencil land at the same place it would if the bus were at rest? Answer: In accord with Newton’s first law, since in both cases there is no horizontal force on the dropped pencil, no change of velocity occurs horizontally. The dropped pencil in the moving bus simply keeps up with you as you move, not changing its velocity in the horizontal direction. Diff: 1 Topic: Newton’s First Law of Motion 2) How does the equilibrium rule, ΣF = 0, relate to Newton’s first law of motion? Answer: The equilibrium rule states Newton’s first law of motion in equation form! So it relates very well. When no net force acts on an object, the motion of the object doesn’t change. If at rest it remains at rest. If moving with constant velocity, it remains moving at constant velocity. Diff: 2 Topic: Newton’s First Law of Motion 28 Copyright © 2017 Pearson Education, Inc. 3) When a boulder and a pebble are dropped, why does the pebble pick up speed as quickly as the boulder, even though less gravity acts on it? In other words, why do both accelerate equally? Answer: Acceleration depends not only on the force of gravity, but also on the mass. If the boulder is fifty times heavier than the pebble, it also has fifty times as much mass. So in accord with Newton’s second law, fifty times as much force on fifty times as much mass gives the same acceleration as one-fiftieth the force on one-fiftieth the mass on the pebble. Both boulder and pebble accelerate equally. If air resistance affects motion, then the accelerations will not be equal. Diff: 3 Topic: Newton’s Second Law of Motion 4) A falling boulder experiences a force, which is responsible for its acceleration. What is the reaction to this force? How can this question be better phrased? Answer: The force that acts on the boulder is Earth pulling down on it. The reaction is the boulder pulling up on Earth. A better-phrased question would be: Earth exerts a downward force on a falling boulder; what is the reaction to this force? The answer follows the rule, “A acts on B, B reacts on A.” Which is to say, the boulder exerts an upward force on Earth. Diff: 1 Topic: Newton’s Second Law of Motion 5) Why will girls wearing gym shoes win in a tug-of-war against boys wearing socks while the activity occurs on a smooth floor? Answer: In any tug of war, the tension on both ends of the rope is the same, so the winning team is the one that exerts more force on the floor. Socks slip easily on a smooth floor, preventing the boys from pushing on and being pushed by the floor. Newton’s third law! Diff: 2 Topic: Newton’s Third Law of Motion 6) A physicist says that a car accelerating along a level road is being propelled by the road. Defend this statement. Answer: It’s true. The tires are made to rotate by the engine, and the tire surfaces are the only points of contact with the road. The turning tires push backward on the road. Interestingly, the tires can only push backward on the road if the road simultaneously pushes forward on the tires. This forward force is the only force that propels the car along the road. Air resistance occurs also, partly counteracting the propulsion by the road. Diff: 2 Topic: Newton’s Third Law of Motion 29 Copyright © 2017 Pearson Education, Inc.