Physics Chapter 5

An Earth satellite is simply a projectile freely falling around the Earth. (A) False (B) True

B

A bullet fired from a rifle begins to fall (A) as soon as it leaves the barrel. (B) after air friction reduces its speed. (C) neither A nor B

A

A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. Neglecting air resistance, where will the bullet be 1 s later? (A) 100 m downrange (B) 50 m downrange (C) 490 m downrange (D) 98 m downrange (E) none of the above

A

A hunter aims a rifle at an angle of 10° below the horizontal. The hunter fires a bullet while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first? (A) the fired one (B) the dropped one (C) Both will hit at the same time.

A

A satellite that maintains a constant speed in orbit follows (A) a circular path. (B) an elliptical path. (C) a straight line path. (D) a parabola.

A

An object is placed exactly halfway between Earth and the Moon. The object will fall toward the (A) Earth. (B) Moon. (C) none of the above

A

Assume that you weight yourself on a bathroom scale. Would the springs inside a bathroom scale be more compressed or less compressed if you weighed yourself in an elevator that was accelerating downward? (A) The springs would be less compressed. (B) The compression of the springs would be unchanged. (C) The springs would be more compressed.

A

Assume that you weight yourself on a bathroom scale. Would the springs inside a bathroom scale be more compressed or less compressed if you weighed yourself in an elevator that was accelerating upward? (A) The springs would be more compressed. (B) The springs would be less compressed. (C) The compression of the springs would be unchanged.

A

Earth's gravitational field extends (A) both inside and outside Earth and throughout the entire universe. (B) only above and beyond Earth's surface and cancels inside Earth. (C) none of the above

A

If Earth's mass decreased to one-half its original mass with no change in radius, then your weight would (A) decrease to one-half your original weight. (B) decrease to one-quarter your original weight. (C) stay the same. (D) none of the above

A

Is it correct to say that the planets of the solar system are simply projectiles falling around the Sun? (A) yes (B) no

A

Is it possible to simulate weight in a space habitat? (A) Yes, weight can be simulated with the centripetal force acting on a person moving in a circular path. (B) Yes, weight can be simulated with the force acting on a person moving uniformly along straight line. (C) Weight cannot be simulated in a space habitat.

A

Suppose you are in an elevator. As the elevator starts upward, its speed will increase. During this time when the elevator is moving upward with increasing speed, your weight will be __________. (A) greater than your normal weight at rest (B) equal to your normal weight at rest (C) less than your normal weight at rest

A

The constant G in Newton's equation for universal gravitation (A) makes the units of measurement consistent. (B) shows gravity to be a relatively huge force. (C) was measured by Newton. (D) produces equilibrium.

A

The crew of a cargo plane wishes to drop a crate of supplies on a target below. To hit the target, when should the crew drop the crate? Ignore air resistance. (A) Before the plane is directly over the target (B) When the plane is directly over the target (C) After the plane has flown over the target

A

The direction of a gravitational field is (A) in the same direction of gravitational attraction. (B) opposite to the direction of gravitational attraction. (C) away from the center of gravity of an object.

A

When the masses of two planets are doubled, the force of attraction between them (A) quadruples. (B) remains the same. (C) doubles.

A

When you whirl a can at the end of a string in a circular path, what is the direction of the force that acts on the can? Neglect the downward pull of gravity. (A) The force is directed toward the center of the circle. (B) The force is directed opposite to the can's velocity. (C) The force is in the same direction as can's velocity. (D) The force is directed outward from the center of the circle.

A

Why does the gravity in the Space Shuttle compare with the gravity on Earth the way it does? (A) The Space Shuttle and the surface of the Earth are about the same distance from the center of the Earth. (B) The Space Shuttle is much closer to the center of the Earth than the surface of the Earth. (C) The Space Shuttle is much farther away from the center of the Earth than the surface of the Earth.

A

A ball is batted upward at an angle. What happens to the vertical component of its velocity as the ball rises? (A) The vertical component of the ball's velocity remains the same. (B) The vertical component of the ball's velocity decreases. (C) The vertical component of the ball's velocity increases.

B

A projectile is fired vertically from the surface of Earth at 10 km/s. The projectile will (A) go into an elliptical orbit about Earth. (B) rise and fall back to Earth's surface. (C) go into circular orbit about Earth. (D) none of the above

B

According to Newton, the greater the masses of interacting objects, the (A) greater the force between them by the square of the masses. (B) greater the gravitational force between them. (C) less the gravitational force between them.

B

An Earth satellite is in an elliptical orbit. The satellite travels fastest when it is (A) farthest from Earth. (B) nearest Earth. (C) It travels at a constant speed everywhere in orbit.

B

Assume that you weight yourself on a bathroom scale. Would the springs inside a bathroom scale be more compressed or less compressed if you weighed yourself in an elevator that was moving downward at constant velocity? (A) The springs would be less compressed. (B) The compression of the springs would be unchanged. (C) The springs would be more compressed.

B

If you are standing on a scale in an elevator, what exactly does the scale measure? (A) your mass (B) the force you exert on the scale (C) the gravitational force exerted on you by Earth

B

If you drop a ball from rest it will fall 5 meters in one second. If you toss the ball horizontally it will fall in one second a vertical distance of (A) more than 5 m. (B) 5 m. (C) 10 m. (D) less than 5 m.

B

Ignoring air drag, what is the maximum speed that can be given to a horizontally moving tennis ball as it clears the net 1.25 m high to remain within the edge of the court, which is 12.0 m distant? (A) 16.0 m/s (B) 24.0 m/s (C) 48.0 m/s (D) 12.0 m/s

B

Inside a freely falling elevator, there would be no (A) gravitational force on you. (B) apparent weight for you. (C) both of the above (D) none of the above

B

Minimal orbit speed about Earth is about 8 km/s. Minimal orbital speed about the Moon would be (A) more than 8 km/s. (B) less than 8 km/s. (C) about 8 km/s.

B

The ______ of an object is a measure of the amount of matter it contains. On the other hand______is a measure of gravitational force on an object. (A) weight, mass (B) mass, weight (C) energy, force (D) momentum, energy

B

The force of gravity acts on all apples on an apple tree. Some apples are twice as far from the ground as others. These twice-as-high apples, for the same mass, have (A) one-quarter the weight. (B) practically the same weight. (C) one-half the weight.

B

Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them (A) remains constant. (B) increases. (C) decreases.

B

Where is your gravity detector? (A) In your chest. (B) Inside your ear. (C) On your phone. (D) In your brain.

B

Which depends on gravity - weight or mass? (A) Both weight and mass depend on gravity (B) Weight depends on gravity (C) Mass depends on gravity

B

earth satellites are typically more than 100 km high so as to be above Earth's (A) gravitational field. (B) atmosphere. (C) both A and B

B

A "weightless" astronaut in an orbiting shuttle is (A) shielded from Earth's gravitational field. (B) beyond the pull of gravity. (C) like the shuttle, pulled by Earth's gravitation. (D) pulled only by gravitation to the shuttle which cancels Earth's gravitational pull. (E) none of the above

C

A ball is batted upward at an angle. With no air drag, what happens to the horizontal component for the ball? (A) The horizontal component of the ball's velocity decreases. (B) The horizontal component of the ball's velocity increases. (C) The horizontal component of the ball's velocity remains the same.

C

A ball is thrown upward and caught when it comes back down. Neglecting air resistance, the speed with which it is caught is (A) more than the speed it had when thrown upward. (B) less than the speed it had when thrown upward. (C) the same as the speed it had when thrown upward.

C

A ball player wishes to determine pitching speed by throwing a ball horizontally from an elevation of 5 m above the ground. The player sees the ball land 20 m down range. What is the player's pitching speed? (A) 25 m/s (B) 5 m/s (C) 20 m/s (D) 10 m/s (E) none of the above

C

A projectile is fired vertically from the surface of Earth at 8 km/s. The projectile will (A) follow an uncertain path. (B) go into circular motion about Earth. (C) rise and fall back to Earth's surface.

C

A projectile is launched at 60° above ground level. What other angle at the same speed will result in the same range? (A) 45°. (B) 15°. (C) 30°. (D) Any angle at 60° or greater.

C

A projectile is launched vertically at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is (A) less than 50 m/s. (B) more than 50 m/s. (C) 50 m/s.

C

A very massive object A and a less massive object B move toward each other under the influence of gravitation. Which force, if either, is greater? (A) the force on B (B) the force on A (C) both forces are the same.

C

An object is thrown vertically into the air. Because of air resistance, the time for its descent will be (A) shorter than the ascent time. (B) equal to the ascent time. (C) longer than the ascent time. (D) not enough information given to say

C

Assume that you weight yourself on a bathroom scale. Would the springs inside a bathroom scale be more compressed or less compressed if you weighed yourself in an elevator that was moving upward at constant velocity? (A) The springs would be less compressed. (B) The springs would be more compressed. (C) The compression of the springs would be unchanged.

C

Compared with the period of satellites in orbit close to Earth, the period of satellites in orbit far from Earth is (A) shorter. (B) the same. (C) longer. (D) not enough information given

C

How does the gravity in the Space Shuttle compare with the gravity on Earth's surface? (A) The gravity in the Space Shuttle is much smaller than the gravity on Earth's surface. (B) The gravity in the Space Shuttle is much larger than the gravity on Earth's surface. (C) The gravity in the Space Shuttle is approximately equal to the gravity on the surface of the Earth.

C

If the mass of Earth somehow increased with no change in radius, your weight would (A) stay the same. (B) decrease. (C) increase also.

C

One's weightlessness in space involves no (A) mass. (B) rotational effects. (C) support force. (D) gravity.

C

Suppose you are in an elevator that is moving upward. As the elevator nears the floor at which you will get off, its speed slows down. During this time when the elevator is moving upward with decreasing speed, your weight will be __________. (A) greater than your normal weight at rest (B) equal to your normal weight at rest (C) less than your normal weight at rest

C

The ground speed of an airplane that has an airspeed of 100 km/h when it is in a 100-km/h crosswind is (A) 100 km/h. (B) 200 km/h. (C) 141 km/h. (D) 150 km/h. (E) 0 km/h.

C

Two motorcycle stunt drivers, one light and the other much heavier, drive their motorcycles up and off an inclined ramp at identical speeds. They both rise in the air and land downrange. Neglecting air drag, the one to attain the greatest height and greatest range is the (A) heavy driver. (B) light driver. (C) both the same

C

Two objects move toward each other because of gravity. As the objects get closer and closer, the acceleration of each (A) decreases. (B) remains constant. (C) increases.

C

When is your weight equal to mg? (A) When you are in an elevator that accelerates downward near the Earth's surface. (B) When you are in an elevator that accelerates upward near the Earth's surface (C) When you are in a state of zero acceleration on the Earth's surface. (D) None of the above.

C

When is your weight greater than mg? (A) When you are in an elevator that accelerates downward near the Earth's surface. (B) When you are in a state of zero acceleration on the Earth's surface. (C) When you are in an elevator that accelerates upward near the Earth's surface. (D) None of the above.

C

When is your weight zero? (A) When you are at rest on the Earth's surface. (B) When you are in an elevator that is moving downward with speed of 10 m/s near the Earth's surface. (C) When you are in free fall. (D) When you are in an elevator that is moving upward with acceleration of 10 m/s2 near the Earth's surface.

C

When the distance between two planets is doubled, the force of attraction between them (A) doubles. (B) decreases to half. (C) decreases to one quarter. (D) remains the same.

C

Why do the astronauts in the Space Shuttle float around? (A) There is no gravity in the Space Shuttle because it is completely enclosed and shielded from the effects of gravity due to the Earth. (B) There is no gravity in the Space Shuttle because it is too far away from the center of the Earth. (C) The Space Shuttle is in free fall, so the shuttle and the astronauts inside it are continuously falling toward the Earth. They thus experience apparent weightlessness.

C

A bullet is fired horizontally with an initial velocity of 300 m/s from a tower that is 20 m high. If air resistance is negligible, the horizontal distance the bullet travels before hitting the ground is (A) 400 m. (B) 500 m. (C) 300 m. (D) 600 m. (E) 200 m.

D

Communications and weather satellites always appear at the same place in the sky. This is because these satellites are (A) moving at a speed just short of escape velocity. (B) beyond the pull of Earth's gravitational field. stationary in space. (C) orbiting Earth with a 24-hour period. (D) none of the above

D

Occupants in a rotating donut-like space habitat experience weight due to (A) gravity. (B) inertia. (C) pulls by nearby planets. (D) a support force.

D

Planets would crash into the Sun if it weren't for (A) the inverse-square law. (B) their relatively small masses. (C) the fact that they are beyond the main gravitation of the Sun. (D) their tangential velocities. (E) their vast distances from the Sun.

D

What does "centripetal" mean? (A) False force. (B) Downward push. (C) Inward pull. (D) Center-seeking.

D

What is Newton's law of gravitation? (A) Every body in the universe attracts every other body with a mutually attracting force. For two bodies, this force is directly proportional to the product of their masses and the distance separating them. (B) Every body in the universe attracts every other body with a mutually attracting force. For two bodies, this force is inversely proportional to the product of their masses and directly proportional to the square of the distance separating them. (C) Every body in the universe repels every other body with a mutually repulsive force. For two bodies, this force is directly proportional to the product of their masses and inversely proportional to the distance separating them. (D) Every body in the universe attracts every other body with a mutually attracting force. For two bodies, this force is directly proportional to the product of their masses and inversely proportional to the square of the distance separating them.

D

What is the effect of air drag on the height and range of batted baseballs? (A) The effect of air drag is that only the height is decreased and the range remains the same. (B) The effect of air drag is that range is decreased and the height is increased. (C) The effect of air drag is that only range is decreased and the height remains the same. (D) The effect of air drag is that both range and height are decreased.

D

What is the force of gravity on a 500-N woman standing on Earth's surface? (A) 50 N (B) 509.8 N (C) 250 N (D) 500 N (E) none of the above

D