MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Transcription

1 Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to A) follow a circular path. B) stop. C) follow a straight-line path. D) slow down. 2) Weigh yourself on a weighing scale and the scale shows your normal weight. If you carefully stand on tiptoes, the scale reading will be A) slightly more. B) about half as much. C) no different. D) slightly less. 1) 2) 3) The amount of force needed to sustain motion of a rock in outer space is 3) A) a force less than its weight if friction is absent. B) a force equal to its weight. C) none of these 4) A block pulled to the left with 15 N and to the right with 5 N at the same time experiences a net force of A) 15 N. B) 5 N. C) 10 N. D) 20 N. 4) 5) If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in 5) A) a straight-line path. B) an inward spiral path. C) an outward spiral path. D) a curved path. 6) A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is A) about 30 m/s. B) more than 30 m/s. C) zero. D) less than 30 m/s but more than zero. 6) 7) When you flick a card from beneath a coin that hardly moves, you're illustrating 7) A) inertia. B) support force. C) equilibrium. D) friction. 8) Galileo taught us that if you roll a ball along a level surface it will 8) A) keep rolling if friction is absent. B) soon roll in the opposite direction. C) soon slow down due to its natural place. D) roll as long as its inertia nudges it along. 9) Burl and Paul paint signs together on a scaffold. Compared to their weights plus the weight of the scaffold, the sum of tensions in the supporting ropes is A) greater. B) zero. C) the same. D) less. 9) 10) The net force acting on an insect falling downward at constant velocity is 10) A) zero. B) upward air resistance. C) the weight of the insect. D) none of the above 1

2 11) Two students engaged in a tug-of-war each pull a rope in opposite directions with a force of 400 N. The net force on the rope is A) zero and rope tension is 800 N. B) 400 N and rope tension is also 400 N. C) 400 N and rope tension is 800 N. D) zero and rope tension is 400 N. 11) 12) A force is a vector quantity because it has both 12) A) magnitude and direction. B) speed and direction. C) action and reaction counterparts. D) mass and velocity. 13) Which of the following is a vector quantity? 13) A) volume B) mass C) area D) none of the above 14) Earth continually moves about 30 km/s through space, which means the wall you stand next to also is moving at 30 km/s. When you jump vertically the wall doesn't slam into you because A) motion of the Sun counteracts your motion. B) the speeds of you and Earth cancel out. C) your upward motion is small compared with Earth's speed. D) you're moving horizontally just as fast as the wall. 14) 15) The support force on a 10-N book at rest on a table is 15) A) dependent on the position of the book. B) slightly greater than 10 N. C) 10 N. D) slightly less than 10 N. 16) Phil leans over the edge of a cliff and throws a rock upward at 5 m/s. Neglecting air resistance, two seconds later the rock's speed is A) 15 m/s. B) zero. C) 5 m/s. D) 10 m/s. 17) A ball rolls along a horizontal track in a certain time. If the track has a small upward dent in it, the time to roll the length of the track will be A) less. B) more. C) the same. 18) At one instant a heavy object in air is moving upward at 50 m/s. One second later its speed is approximately A) 60 m/s. B) 50 m/s. C) 55 m/s. D) 40 m/s. 19) Jogging Jake runs at 4 m/s along a train flatcar that moves at 10 m/s in the same direction. Jake's speed relative to the ground is A) 14 m/s. B) 6 m/s. C) 10 m/s. D) none of the above 16) 17) 18) 19) 2

3 20) The vertical height attained by a basketball player who achieves a hang time of a full 1 s is about 20) A) 2.5 m. B) 1.2 m. C) more than 2.5 m. D) 0.8 m. E) 1 m. 21) What is the acceleration of a car that starts from rest and 5 seconds later reaches a speed of 20 m/s? 21) A) 1 m/s2 B) 2 m/s2 C) 3 m/s2 D) 4 m/s2 E) 5 m/s2 22) A bird flying at 8 km/h in a 6-km/h crosswind has a resultant speed of 22) A) 14 km/h. B) 8 km/h. C) 10 km/h. D) 6 km/h. 23) A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always A) directed upward. B) opposite its velocity. C) in the direction of motion. D) directed downward. 24) A bullet is dropped into a river from a very high bridge at the same time as another bullet is fired straight downward from a rifle. Neglecting air resistance, the acceleration just before striking the water is A) greater for the fired bullet. B) greater for the dropped bullet. C) the same for each bullet. D) none of the above 23) 24) 25) The time it takes a projectile fired straight up at 10 m/s to reach the top of its path is about 25) A) 10 s. B) 2 s. C) 1 s. D) not enough information 26) The accelerations possible for a ball on an inclined plane 26) A) range from g to infinity. B) range from zero to g. C) have no limit. 27) At one instant an object in free fall is moving downward at 50 m/s. One second later its speed is 27) A) 60 m/s. B) 50 m/s. C) 55 m/s. D) 25 m/s. E) 100 m/s. 28) A ball is projected 125 meters straight upward and then falls the same distance back to its starting point. Neglecting air resistance, its total time in the air is about A) 5 s. B) 10 s. C) more than 20 s. D) 15 s. 28) 29) If a rocket initially at rest accelerates at a rate of 50 m/s2 for one minute, its speed will be 29) A) 500 m/s. B) 50 m/s. C) 3000 m/s. D) 3600 m/s. 30) 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 will get to the ground first? A) The heavy man B) not enough information C) The light woman D) Both should arrive at the same time. 30) 3

4 31) An astronaut on another planet drops a 1-kg rock from rest. The astronaut notices that the rock falls 2 meters straight down in one second. On this planet, how much does the rock weigh? A) 10 N B) 1 N C) 5 N D) 4 N 32) You drive your car at a constant 60 km/h along the highway. You 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) decrease in speed if no other forces act. B) continue moving at 40 km/h. C) momentarily regain its higher initial speed. 31) 32) 33) At equilibrium on a bathroom weighting scale, the downward pull of gravity on you is balanced by 33) A) your weight. B) your mass. C) an upward support force. 34) A 1-kg mass at the Earth's surface weighs 34) A) 5 N. B) 12 N. C) 1 N. D) 10 N. 35) A tow truck exerts a force of 3000 N on a car, which then accelerates at 2 m/s2. What is the mass of the car? A) 1500 kg B) 1000 kg C) 3000 kg D) 500 kg E) none of these 36) Suppose 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) continues at the speed it had when it encountered the second force. B) is brought to a rapid halt. C) theoretically tends to accelerate toward the speed of light. D) decelerates gradually to a halt. 35) 36) 37) The force required to maintain a constant velocity for an astronaut in free space is equal to 37) A) zero. B) the force required to stop the astronaut. C) the mass of the astronaut. D) the weight of the astronaut. 4

5 38) A feather and a coin will have equal accelerations when falling in a vacuum because 38) A) the force of gravity does not act in a vacuum. B) the force of gravity is the same for each in a vacuum. C) their velocities are the same. D) the ratio of both the feather's and coin's weight to mass is the same. 39) A heavy ball hangs by a string, with a second string attached to its bottom. A slow pull on the bottom string breaks the A) top or bottom string equally. B) bottom string. C) top string. 40) When a constant and sustained upward force acts on a rocket, its acceleration increases mainly because A) No way, for acceleration would be constant. B) the mass of the rocket decreases as fuel is burned. C) gravity becomes weaker with increased distance. 39) 40) 41) A vertical vector of 3 units combined with a horizontal vector of 4 units has a resultant of 41) A) 1 unit. B) 7 units. C) 5 units. 42) The force due to gravity that acts on a block of ice that slides down an icy ramp 42) A) decreases as the slope of the ramp increases. B) becomes greatest when the ramp is vertical. C) remains equal to mg at all angles. 43) A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The vehicle that undergoes the greatest change in velocity will be the A) same for both. B) Mack truck. C) Volkswagen. 44) Joshua is attracted toward Earth by a 500-N gravitational force. The Earth is attracted toward Joshua with a force of A) 500 N. B) zero. C) 250 N. D) 1000 N. 45) When a boxer hits a punching bag, the strength of his punch depends on how much force the bag can A) endure. B) soften. C) exert on the boxer's fist. 43) 44) 45) 46) For every action force, there must be a reaction force that 46) A) is slightly smaller in magnitude than the action force. B) is equal in magnitude. C) is slightly larger in magnitude than the action force. D) acts in the same direction. 47) A shoe on an inclined surface barely remains at rest when friction equals the 47) A) component of mg parallel to the surface. B) component of mg perpendicular to the surface. C) weight mg of the shoe. D) none of the above 5

6 48) The force with which Earth pulls on the Moon is 48) A) somewhat greater than Moon's pull on Earth. B) equal in magnitude to the force that Moon pulls on Earth. C) the only force acting between Earth and Moon. 49) As the sloped surface supporting a shoe becomes steeper 49) A) friction needed to keep it at rest increases. B) the normal force becomes less. C) the shoe's weight mg remains unchanged. D) all of the above 50) A karate chop is more effective if one's hand 50) A) extends the time upon impact. B) bounces upon impact. C) follows through upon impact. 51) A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force on her hand is A) zero. B) less than the force applied to the cement block. C) more than the force applied to the block. D) the same as the force applied to the block. E) need more information 52) A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest. Both move with a combined momentum of A) 1 unit. B) less than 1 unit. C) more than 1 unit. D) need more information 53) Padded dashboards in cars are safer in an accident than non-padded ones because passengers hitting the dashboard encounter A) shorter time of contact. B) lengthened time of contact. C) decreased impulse. D) increased momentum. 54) A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of A) more than 5 kg m/s. B) 1 kg m/s. C) 0 kg m/s. D) 2 kg m/s. E) 5 kg m/s. 55) A car traveling along the highway brakes to a stop over a certain distance. More braking force is required if the car has A) more momentum. B) more mass. C) less stopping distance. D) all of the above 51) 52) 53) 54) 55) 6

7 56) The conservation of momentum is most closely related to 56) A) Newton's 1st law. B) Newton's 3rd law. C) Newton's 2nd law. D) Newton's law of gravity 57) When a vertically falling firecracker bursts, the vector sum of momentum fragments 57) A) in the horizontal direction cancels to zero. B) in the vertical direction equals the momentum of the firecracker before bursting. C) both of these D) neither of these 58) The fastest moving planet in a solar system is the 58) A) planet nearest the Sun. B) all move at the same speed. C) most massive planet. D) smallest planet. E) planet farthest from the Sun. 59) For all paths of Earth satellites, one focus of the path is 59) A) Earth's center. B) the location from which the satellite was launched. C) the Sun's center. D) need more information 60) The kinetic energy of a planet is maximum when it is 60) A) closest to the Sun. B) least accelerating. C) farthest from the Sun. D) none of the above 61) Consider a monkey wrench released at rest at the far edge of the solar system. Suppose that it drops to Earth by virtue of only Earth gravity. It will strike Earth's surface with a speed of about A) 8 km/s. B) the speed of light. C) 11.2 km/s. D) 10 m/s. 61) 62) An Earth satellite in an elliptical orbit travels fastest when it is 62) A) everywhere along its orbit. B) farthest from Earth. C) nearest Earth. 63) An Earth satellite in an elliptical orbit has its smallest speed 63) A) when getting farther from Earth. B) when farthest from Earth. C) closest to Earth. D) need more information 64) When the potential energy of a satellite decreases 64) A) its distance from the orbiting body increases. B) kinetic energy also decreases. C) its kinetic energy correspondingly increases. D) none of the above 7

8 65) When a rocket ship gaining speed in outer space runs out of fuel, it 65) A) gains speed for a short time, then slows down to a constant velocity. B) no longer gains speed. C) gains speed for a short time, slows down, and eventually stops. 66) The force that causes Earth to orbit the Sun is due to gravity, while the force needed to keep Earth moving as it circles the Sun is A) due to both inertia and gravity. B) inertia. C) no force at all. D) due to gravity. 66) 67) The first scientist to be credited for postulating that Earth circled the Sun was 67) A) Aristotle. B) Galileo. C) Newton. D) Copernicus. 68) If Burl carries Paul piggy-back while standing in the middle of a scaffold, the tensions in the two supporting ropes would A) be equal. B) cancel to zero. C) be in dynamic equilibrium. D) more easily support Burl and Paul. 68) 69) The equilibrium rule applies to 69) A) quantities that are equal in magnitude. B) scalar quantities. C) any kind of quantities. D) vector quantities. 70) Compared with hang time on Earth, hang time on the Moon would be 70) A) the same. B) greater. C) less. 71) The speedometer of an automobile reads 71) A) accelerated speed. B) average speed. C) instantaneous speed. 72) If a car increases its velocity from zero to 60 m/s in 10 seconds, its acceleration is 72) A) 600 m/s2. B) 3 m/s2. C) 60 m/s2. D) 6 m/s2. 73) A seagull flying at 10 km/h in a 10-km/h crosswind has a resultant speed of 73) A) 20 km/h. B) more than 20 km/h. C) about 14 km/h. D) 10 km/h. 74) A freely-falling watermelon falls with constant 74) A) speed. B) velocity. C) acceleration. D) distances each successive second. 75) A 10-kilogram block with an initial velocity of 10 m/s slides 10 meters across a horizontal surface and comes to rest. It takes the block 2 seconds to stop. The stopping force acting on the block is about A) 10 N. B) 50 N. C) 25 N. D) 5 N. 75) 8

9 76) The newton is a unit of 76) A) inertia. B) mass. C) density. D) force. 77) Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has the same 77) A) volume. B) weight. C) mass. D) all of the above 78) A 500-N parachutist opens his chute and experiences an air resistance force of 800 N. The net force on the parachutist is then A) 300 N upward. B) 500 N upward. C) 300 N downward. D) 800 N downward. E) 500 N downward. 79) Nellie tosses a ball upward at an angle. Neglecting air resistance, the horizontal component of the initial velocity A) remains constant. B) increases with time. C) decreases with time. 80) An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the A) arrow's push against the bowstring. B) grip of the archer's hand on the bow. C) friction of the ground against the archer's feet. D) combined weight of the arrow and bowstring. 81) A river 100 m wide flows due south. A boat that goes 1 m/s relative to the water is pointed due east as it crosses from the west bank. The boat crosses in A) 100 s. B) 141 s. C) 50 s. D) 200 s. 82) Consider massive gliders that slide friction-free along a horizontal air track. Glider A has a mass of 1 kg, a speed of 1 m/s, and collides with Glider B that has a mass of 5 kg and is at rest. If they stick upon collision, their speed after collision will be A) 1 m/s. B) 1/5 m/s. C) 1/4 m/s. D) 1/6 m/s. 78) 79) 80) 81) 82) 83) When bullets are fired from an airplane in the forward direction, the momentum of the airplane is 83) A) decreased. B) increased. C) unchanged. 9

10 84) Two vehicles with equal magnitudes of momentum traveling at right angles to each other undergo an inelastic collision. The magnitude of momentum for the combined wreck is A) the same as the magnitude of momentum of either car before collision. B) greater than the magnitude of momentum of either car before collision. C) less than the magnitude of momentum of either car before collision. D) none of the above 85) A ball is thrown upward and caught when it returns. Compared with its initial speed and in the presence of air resistance, the speed with which it is caught is A) less. B) more. C) the same. D) need more information. 84) 85) 86) Newton hypothesized that the forces acting on planets was 86) A) perpendicular to their directions of travel. B) along their directions of travel. C) toward the Sun. D) none of the above 87) A pair of wires support a heavy painting. Tension in the wires is greater when they are 87) A) the same regardless of the wire orientation. B) not vertical. C) vertical. D) none of the above 88) The resultant of a 40-N force at right angles to a 30-N force is 88) A) 40 N. B) 30 N. C) 50 N. D) greater than 50 N. 89) The average speed of a horse that gallops 10 kilometers in 30 minutes is 89) A) 30 km/h. B) 15 km/h. C) 40 km/h. D) 20 km/h. 90) 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 becomes A) 0 m/s2. B) infinite. C) 5 m/s2. D) 10 m/s2. 91) A pair of equal-length vectors at right angles to each other have a resultant. If the angle between the vectors is less than 90, their resultant is A) the same. B) less. C) greater. 90) 91) 92) The total momentum of a flock of identical birds could be zero only if the birds are 92) A) taking off from the ground. B) very tired and coming down to rest. C) flying in different directions. D) flying in the same direction. 93) Project a cannonball from atop Newton's hypothetical mountain at 8 km/s and it orbits Earth. Project it at 9 km/s and the shape of the orbit is A) an ellipse. B) a wide parabola. C) a somewhat larger circle. 93) 10

11 94) When you stand at rest on a pair of bathroom scales, the reading on each scale 94) A) add up to equal your weight. B) is half your weight. C) equals your weight. 95) When a ball thrown straight upwards reaches the very top of its path, its acceleration is 95) A) 10 m/s2. B) 5 m/s2. C) zero. D) none of the above 96) When a falling object has reached its terminal velocity, its acceleration is 96) A) constant. B) zero. C) g. 97) A player hits a ball with a bat. If action is the force of the bat against the ball, reaction is the 97) A) weight of the ball. B) force that the ball exerts on the bat. C) air resistance on the ball. D) weight of the bat. E) grip of the player's hand against the ball. 98) A sandbag motionless in outer space is hit by a three-times-as massive sandbag moving at 12 m/s. They stick together and move at a speed of A) 6 m/s. B) 3 m/s. C) 8 m/s. D) 4 m/s. 99) Both Newton and Kepler considered forces on the planets. Kepler mistakenly hypothesized the direction of the forces to be A) perpendicular to their directions of travel. B) along their directions of travel. C) toward the Sun. D) none of the above 98) 99) 11

12 Answer Key Testname: PRACTICE MIDTERM 1) C 2) C 3) C 4) C 5) A 6) A 7) A 8) A 9) C 10) A 11) D 12) A 13) D 14) D 15) C 16) A 17) B 18) D 19) A 20) B 21) D 22) C 23) D 24) C 25) C 26) B 27) A 28) B 29) C 30) A 31) D 32) B 33) C 34) D 35) A 36) A 37) A 38) D 39) C 40) B 41) C 42) C 43) C 44) A 45) C 46) B 47) A 48) B 49) D 50) B 12

13 Answer Key Testname: PRACTICE MIDTERM 51) D 52) A 53) B 54) B 55) D 56) B 57) C 58) A 59) A 60) A 61) C 62) C 63) B 64) C 65) B 66) C 67) D 68) A 69) D 70) B 71) C 72) D 73) C 74) C 75) B 76) D 77) E 78) A 79) A 80) A 81) A 82) D 83) A 84) B 85) A 86) C 87) B 88) C 89) D 90) A 91) C 92) C 93) A 94) A 95) A 96) B 97) B 98) E 99) B 13