# Physical Science 1st test

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Ch. 2

a. speed

b. velocity

### Acceleration occurs when an object undergoes a. a speed increase b. a speed decrease c. a change in the direction of travel d. any of the above

d. any of the above

c. Initial speed

b. 0 km/h

### According to Galileo, an object moving without opposing friction or other opposing forces will. a. still need a constant force to keep it moving at a constant speed. b. need an increasing force, or it will naturally slow and then come to a complete stop. c. continue moving at a constant speed. d. undergo a gradual acceleration.

c. continue moving at a constant speed.

### In free fall, an object is seen to have a (an) a. constant velocity. b. constant acceleration. c. increasing acceleration. d. decreasing acceleration.

b. constant acceleration.

### A tennis ball is hit, causing it to move upward from the racket at some angle to the horizon before it curves back to the surface in the path of a parabola. While it moves along this path, a. the horizontal speed remains the same. b. the vertical speed remains the same. c. both the horizontal and vertical speeds remain the same. d. both the horizontal and vertical speeds change.

a. the horizontal speed remains the same.

b. acceleration.

d. Three or more

b. increasing.

a. constant.

### Two objects are released from the same height at the same time, and on has twice the weight of the other. Ignoring air resistance, a. the heavier object hits the ground first. b. the lighter object hits the ground first. c. they both hit at the same time. d. whichever hits first depends on the distance dropped

c. they both hit at the same time.

### A ball rolling across the floor slows to a stop because a. there is a net force acting on it. b. the force that started it moving wears out. c. the forces are balanced. d. the net force equals zero.

a. there is a net force acting on it.

### The basic difference between instantaneous and average speed is that a. instantaneous speed is always faster than average speed. b.average speed is for a total distance over a total time of trip. c. average speed is the sum of two instantaneous speeds, divided by 2. d. the final instantaneous speed is always the fastest speed.

b.average speed is for a total distance over a total time of trip.

a. Yes

c. acceleration.

### Considering the forces on the system of you and a bicycle as you pedal the bike at a constant velocity in a horizontal straight line, a. the force your are exerting on the pedal is greater than the resisting forces. b. all forces are in balance, with the net force equal to zero. c. the resisting forces of air and tire friction are less than the force you are exerting. d. the resisting forces are greater than the force you are exerting.

b. all forces are in balance, with the net force equal to zero.

### Newton's first law of motion describes a. the tendency of a moving or stationary object to resist any change in its state of motion. b. a relationship between an applied force, the mass, and the resulting change of motion that occurs from the force. c. how forces always occur in matched pairs. d. none of the above.

a. the tendency of a moving or stationary object to resist any change in its state of motion.

### You are standing freely on a motionless shuttle bus. When the shuttle bus quickly begins to move forward, you a. are moved to the back of the shuttle bus as your move forward over the surface of Earth. b. stay in on place over the surface of Earth as the shuttle has moves form under you. c. move along with the shuttle bus. d. feel a force toward the side of the shuttle bus.

b. stay in on place over the surface of Earth as the shuttle has moves form under you.

c. inertia

c. N

### Newton's third law of motion states that forces occur in matched pairs that act in opposite directions between two different bodies.This happens a. rarely. b. sometimes. c. often but not always. d. every time two bodies interact.

d. every time two bodies interact.

a. doubled.

### If you double the mass of a cart while it is undergoing a constant unbalanced force, the acceleration will be a. doubled. b. increased fourfold. c. one-half as much. d. one-fourth as much.

c. one-half as much.

### Doubling the distance between the center of an orbiting satellite and the center of Earth will result in what change in the gravitational attraction of Earth for the satellite? a. One-half as much b. One-fourth as much c. Twice as much d. Four times as much

b. One-fourth as much

### If a ball swinging in a circle on a string is moved twice as fast, the force on the string will be a. twice as great. b. four times as great. c. one-half as much. d. one-fourth as much.

b. four times as great.

### A ball is swinging in a circle on a string when the string length is doubled. At the same velocity, the force on the string will be a. twice as great. b. four times as great. c. one-half as much. d. one-fourth as much.

c. one-half as much.

### Two identical moons are moving in identical circular paths, but one moon is moving trice as fast as the other. Compared to the slower moon, the centripetal force requited to keep the faster moon on the path is a. twice as much. b. one-half as much. c. four times as much. d. one-fourth as much.

c. four times as much.

### Which undergoes a greater change of momentum, a golf ball or the head of a golf club, when the ball is hit from a golf tee? a. The ball undergoes a greater change, b. The head of the club undergoes a greater change. c. Both undergo the some change but in opposite directions. d. The answer depends on how fast the club is moved

c. Both undergo the some change but in opposite directions.

### Newton's law of gravitation tells us that a. planets are attracted to the Sun's magnetic field. b. objects and bodies have weight only on the surface of Earth. c. every object in the universe is attracted to every other object in the universe. d. only objects in the solar system are attracted to Earth.

c. every object in the universe is attracted to every other object in the universe.

### An astronaut living on a space station that is orbiting Earth will a. experience zero gravity. b. weigh more than she did on Earth. c. be in free fall, experiencing apparent weightlessness. d. weigh the same as she would on the Moon.

c. be in free fall, experiencing apparent weightlessness.

b. weight.

c. Twice as long

b. one-half.

### You are moving a grocery cart at a constant speed in a straight line down the aisle of a store. For this situation, the forces on the cart are a. unbalanced, in the direction of the movement. b. balanced, with a net force of zero. c. equal to the force of gravity acting on the cart. d. greater than the frictional forces opposing the motion of the cart.

d. greater than the frictional forces opposing the motion of the cart.

### You are outside a store, moving a loaded grocery cart down the street on a very steep hill. It is difficult, but you are able to pull back on the handle and keep the cart moving down the street in a straight line and at a constant speed. For this situation, the forces on the cart are. a. unbalanced, in the direction of the movement b. balanced, with a net force of zero. c. equal to the force of gracty acting on the cart. d. greater than the frictional forces opposing the motion of the cart.

d. greater than the frictional forces opposing the motion of the cart.

### Neglecting air resistance, a ball in free fall near Earth's surface will have a. constant speed and constant acceleration. b. increasing speed and increasing acceleration. c. increasing speed and decreasing acceleration. d. increasing speed and constant acceleration.

d. increasing speed and constant acceleration.

### From a bridge, a ball is thrown straight up at the same time a ball is thrown straight down with the same initial speed. Neglecting air resistance, which ball will have a a greater sped when it hits the ground? a. The one thrown straight up. b. The one thrown straight down. c. Both balls would have the same speed.

c. Both balls would have the same speed.

a. 9.8 m/s2

### A gun is aimed horizontally at the center of an apple hanging from a tree. The instant the gun is fired, the apple falls and the bullet a. hits the apple b. arrives late, missing the apple. c. arrives early, missing the apple. d. may or may not hit the apple, depending on how fast it is moving.

a. hits the apple

### 43. According to the third law of motion, which of the following must be true about a car pulling a trailer? a. The car pulls on the trailer and the trailer pulls on the car with an equal and opposite force Therefore, the net force is zero and the trailer cannot move. b. Since they move forward, this means the car is pulling harder on the trailer than the trailer is pulling on the car. c. The action force form the car is quicker than the reaction force form the trailer, so they move forward. d. The action-reaction forces between the car and trailer are equal, but the force between the ground and car pushes them forward.

d. The action-reaction forces between the car and trailer are equal, but the force between the ground and car pushes them forward.

### A small sports car and large SUV collide head on and stick together without sliding. Which vehicle had the larger momentum change? a. The small sports car. b. The large SUV. c. It would be equal for both.

c. It would be equal for both.

### Again consider the small sports car and large SUV that collided head on and stuck together without sliding. Which vehicle mush have experienced the larger deceleration during the collision? a. The small sports car. b. The large SUV. c. It would be equal for both.

a. The small sports car.

### An orbiting satellite is moved from 10,000 to 30,000 km from Earth. This will result in what change in the gravitational attraction between Earth and the satellite? a. None-the attraction is the same. b. One-half as much c. One-fourth as much. d. One-ninth as much.

d. One-ninth as much

### Newton's law of gravitation considers the product of two masses because a. the larger mass pulls harder on the smaller mass. b. both masses contribute equally to the force of attraction. c. the larger mass is considered before the smaller mass. d. the distance relationship is one of an inverse square.

b. both masses contribute equally to the force of attraction.

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