physics chapter 4

A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. Neglecting air resistance, how far downrange will the bullet be 1 s later? 50 m 100 m 98 m 500 m none of the above

100 m

Escape speed from Earth is 42.2 km/s. 9.8 km/s. 11.2 km/s. 8 km/s.

11.2 km/s.

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? 20 m/s 25 m/s 10 m/s 5 m/s none of the above

20 m/s

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? 24.0 m/s 16.0 m/s 48.0 m/s 12.0 m/s

24.0 m/s

What is the force of gravity on a 500-N woman standing on Earth's surface? 250 N 500 N 598 N 5000 N 50 N

500 N

Dwarf planet Pluto was discovered by perturbations of Saturn. Uranus and Neptune. Jupiter. all of the above

Uranus and Neptune.

The planet Neptune was discovered by perturbations of Pluto. Uranus. its moons. none of the above

Uranus.

When the distance between two stars decreases by half, the force between them decreases by one-half. decreases by one-quarter. increases to twice as much. increases to four times as much. stays the same.

increases to four times as much.

Strictly speaking, when you step off a curb you are momentarily in orbit. weightless. in space.

weightless

If the Sun were twice as massive, its pull on the Earth would double. Earth's pull on the Sun would double. both neither

both

A hunter fires a bullet from a horizontally-held rifle while simultaneously dropping another bullet from the side of the rifle. Which bullet hits the ground first? the dropped one the fired one both hit at the same time

both hit at the same time

What is the shape of the orbit when the velocity of the satellite is everywhere perpendicular to the force of gravity? circle triangle square ellipse

circle

Acceleration is greatest for a satellite in elliptical orbit when it is farthest from Earth. closest to Earth. same at both places

closest to Earth.

The force of gravity does work on a satellite when it is in elliptical orbit. circular orbit. both neither

elliptical orbit.

An Earth satellite is in an elliptical orbit. The satellite travels slowest when it is farthest from the Earth. nearest the Earth. neither

farthest from the Earth.

How far must one travel to completely be beyond Earth's gravity? to a region above the Earth's atmosphere forget it; you can't travel far enough to a region beyond the solar system to a region well beyond the Moon

forget it; you can't travel far enough

The Sun is spherical due to Earth and Moon circling it. Earth circling it. gravitation. none of the above

gravitation.

Consider two planets in space that gravitationally attract each other. If the mass of one planet is doubled, and the distance between them doesn't change, then the force between them is one-quarter. four times as much. twice as much. half as much. none of the above

half as much

If the mass of Earth somehow increased with no change in radius, your weight would increase also. remain the same. decrease.

increase also

If the radius of the Earth somehow decreased with no change in mass, your weight would decrease. increase. not change.

increase.

Two objects move toward each other due to gravity. As the objects get closer and closer, the acceleration of each increases. remains constant. decreases.

increases

An object is thrown vertically into the air. Because of air resistance, the time for its descent will be equal to the ascent time. shorter than the ascent time. longer than the ascent time. not enough information

longer than the ascent time.

A lunar month is about 28 days. If the Moon were farther from Earth than it is now, the lunar month would be about 28 days. more than 28 days. less than 28 days.

more than 28 days.

Minimal orbit speed about Earth is about 8 km/s. Minimal orbital speed about Jupiter would be less than 8 km/s. about 8 km/s. more than 8 km/s.

more than 8 km/s.

The period of a satellite, the time it takes for a complete revolution, depends on the satellite's mass. radial distance. weight. all the above none of the above

radial distance.

A rock is thrown upward at 50° with respect to the horizontal. As it rises, its horizontal component of velocity remains unchanged. decreases. increases.

remains unchanged.

If your mass remained the same while the mass of Earth doubled while staying the same size, your weight would be eight times as much as now. quadruple. double. be the same. none of the above

the same

A ball is thrown upwards and caught when it returns. Neglecting air resistance, the speed with which it is caught is more than its initial speed. less than its initial speed. the same as its initial speed.

the same as its initial speed.

Compared to the speed a satellite loses when traveling from nearest to farthest points from Earth, the speed gained when returning from farthest to nearest is the same. more. less.

the same.

The speeds of the planets about the Sun depend on their distances from the Sun. the masses of the planets. both neither

their distances from the Sun

If a projectile is fired straight up at a speed of 10 m/s, neglecting air resistance, the time it takes to reach the top of its path is 1 s. 2 s. 10 s. not enough information

1 s

A projectile is thrown into the air at an angle of 50° and lands on a target that is at the same level the projectile started. With no air resistance it will also land on the target if it is thrown at an angle of 45°. 60°. 55°. 40°. none of the above

40

A ball is thrown horizontally from the top of a tall cliff. Three seconds later, the ball has fallen a vertical distance of 45 m. 30 m. 20 m. depends on the initial horizontal speed of the ball

45 m.

Consider a space pod somewhere between Earth and the Moon, at just the right distance so that the gravitational attractions to Earth and the Moon are equal. Is this location nearer Earth or the Moon? nearer the Moon nearer the Earth

nearer the moon

The amount of gravitational force that acts on a space vehicle that orbits Earth is nearly as much as the vehicle's weight on Earth's surface. nearly zero. the same as the vehicle's weight on the Earth's surface.

nearly as much as the vehicle's weight on Earth's surface.

Without air resistance, a projectile fired horizontally at 8 km/s from a mountaintop will accelerate downward at g as it moves horizontally. trace a curve that matches Earth's curvature. return to its starting position and repeat its falling behavior. all the above. none of the above.

all the above.

A bullet fired from a rifle begins to fall as soon as it leaves the barrel. after air friction reduces its speed. neither

as soon as it leaves the barrel.

An astronaut lands on a planet that has the same mass as Earth but half the diameter. How does the astronaut's weight differ from that on Earth? Astronaut weights half as much as on Earth. Astronaut weights quarter as much as on Earth. Astronaut has four times as much weight as on Earth. Astronaut has two times as much weight as on Earth. Astronaut has the same weight on this planet and on Earth.

astronaut has four times as much weight on Earth

Earth satellites are typically more than 100-km high so as to mainly be above the Earth's atmosphere. gravitational influence. both

atmosphere.

An airplane flies at 40 m/s at an altitude of 50 m. The pilot drops a heavy package, which falls and strikes the ground. Neglecting air resistance, where does the package land? 400 m behind the plane beneath the plane more than 500 m behind the plane 500 m behind the plane none of the above

beneath the place

A rock is thrown upward at 50° with respect to the horizontal. As it rises, its vertical component of velocity decreases. increases. remains unchanged.

decreases

An object is placed exactly halfway between the Earth and the Moon. The object will fall toward the Moon. Earth. neither

Earth

A satellite near Earth makes a full circle in about 90 minutes. How long would a satellite located as far away as the Moon take to orbit Earth? less than 90 minutes about 28 days 90 minutes not enough information none of the above

about 28 days

The circular orbit of a satellite orbiting the Earth is characterized by a constant speed. radial distance. acceleration. all the above none of the above

all the above

For the astronauts inside an orbiting space vehicle, there is no force of Earth's gravity acting on them. This statement is always false. always true while in orbit. sometimes true while in orbit.

always false

A supplier wants to make a profit by buying gold by weight at one altitude and selling it at the same price per kilogram at another altitude. The supplier should disregard altitude because it makes no difference. buy at a low altitude and sell at a high altitude. buy at a high altitude and sell at a low altitude.

buy at a high altitude and sell at a low altitude

After a rock that is thrown straight up reaches the top of its path and is starting to fall back down, its acceleration is less than when it was at the top of its path. greater than when it was a the top of its path. the same as it was at the top of its path.

c

The Earlybird communication satellite hovers over the same point on Earth's equator indefinitely because it pulls as hard on Earth as Earth pulls on it. it is kept aloft by ground control. forces other than Earth's gravity act on it. its orbital period is 24 hours. it is beyond the main pull of Earth gravity.The

its orbital period is 24 hours.

A lunar month is about 28 days. If the Moon were closer to Earth than it is now, the lunar month would be more than 28 days. less than 28 days. unchanged at 28 days.

less than 28 days.

Minimal orbit speed about Earth is about 8 km/s. Minimal orbital speed about the Moon would be about 8 km/s. less than 8 km/s. more than 8 km/s.

less than 8 km/s.

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

orbiting Earth with a 24-hour period.

Roll a bowling ball off the edge of a table. As it falls, its horizontal component of motion decreases. remains constant. increases.

remains constant.

An astronaut lands on a planet that has the same mass as Earth but twice the diameter. How does the astronaut's weight differ from that on Earth? The astronaut weighs two times larger than on Earth. The astronaut weighs one-quarter as much as on Earth. The astronaut weighs halved as much as on Earth. The astronaut weighs four times larger than on Earth. The astronaut has the same weight than on Earth.

The astronaut weighs one-quarter as much as on Earth.

Two projectiles are fired at equal speeds but different angles. One is fired at an angle of 30° and the other at 60°. With no air resistance, the projectile to hit the ground first will be the one fired at 30°. 60°. both hit at the same time

a

What prevents satellites such as the space shuttle from falling? centripetal force the absence of air resistance centrifugal force gravity nothing, they continually fall around and around Earth

nothing, they continually fall around and around Earth

Newton discovered gravity. that gravity is universal. neither

that gravity is universal.

The reason the Moon does not crash into Earth is that the Moon has less mass than Earth. the Moon has a sufficient tangential speed. Earth's gravitational field is weak at the Moon. the gravitational pull of other planets keeps the Moon up. none of the above

the Moon has a sufficient tangential speed.

Escape speed for a rocket is less from the Moon. Earth. the Sun. same for each

the Moon.

Escape speed for a rocket is greatest from Earth. the Moon. the Sun. same for each

the Sun.

A hunter aims a rifle at an angle of 10° above the horizontal. The hunter fires a bullet while simultaneously dropping another bullet from the side of the rifle. Which bullet hits the ground first? the fired one the dropped one both hit at the same time

the dropped one

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

the force on B

The fastest moving planet in a solar system is any planet, for they all move at the same speed. the planet nearest the Sun. the most massive planet. the smallest planet. the planet farthest from the Sun.

the planet nearest the Sun.

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

their tangential velocities.

Is there change in the force of gravity between two objects when their masses are doubled and the distance between them is also doubled? The force of gravity is tripled. The force of gravity is quadrupled. The force of gravity is doubled. There is no change.

there is no change

An Earth satellite is simply a projectile freely falling around the Earth. false true sometimes true and sometimes false

true

Inside a freely falling elevator you would experience no gravitational force. weight. both none of the above

weight

Inside a freely falling elevator your acceleration is zero. weight is zero. gravitational interaction with Earth is zero. all the above none of the above

weight is zero.

A bullet fired horizontally hits the ground in 0.5 s. If it had been fired with twice the velocity it would have hit the ground in 0.5 s. less than 0.5 s. more than 0.5 s.

.5 s

A woman who normally weighs 400 N stands on top of a very tall ladder so she is one Earth-radius above Earth's surface. What is her weigh there? zero 200 N 100 N 400 N none of the above

400 N

A stone is thrown horizontally from the top of a cliff. One second after leaving your hand it drops a vertical distance of 15 m. 5 m. 10 m.

5 m

Throw an object at an angle upward. With no gravity it will follow a straight-line path. But because of gravity, at the end of 1 s, it is 15 m below the straight line. 5 m below the straight line. 10 m below the straight line.

5 m below the straight line.

A projectile is launched straight upward at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is more than 50 m/s. less than 50 m/s. 50 m/s.

50 m/s.

A projectile is launched at an angle of 15° above the horizontal and lands downrange. With no air resistance, what other projection angle for the same speed would produce the same downrange distance? 50° 45° 75° 90° 30°

75

The planet Jupiter is about 300 times as massive as Earth, yet on its surface you would weigh only about 3 times as much. This is because Jupiter's radius is 10 times Earth's radius. your mass is 100 times less on Jupiter. you are 100 times more weightless there. Jupiter is significantly farther from the Sun. none of the above

Jupiter's radius is 10 times Earth's radius.

Earth is farther away from the Sun in June and closest in December. In which of these two months is Earth moving faster around the Sun? The traveling speed of the Earth about the Sun always is the same. The Earth travels faster about the Sun in June than in December. The Earth travels faster about the Sun in December than in June.

The Earth travels faster about the Sun in December than in June

The International Space Station orbits at an average 360-km altitude so that it is mainly above Earth's gravitation. atmosphere. both

atmosphere.

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 light driver. heavy driver. both the same

both the same

If Earth's mass decreased to one-half its original mass with no change in radius, your weight would decrease to one-half. decrease to one-quarter. remain the same. none of the above

decrease to one-half.

According to Newton, the greater the masses of interacting objects, the greater the force between them by the square of the masses. less the gravitational force between them. greater the gravitational force between them.

greater the gravitational force between them.

Two objects move toward each other due to gravity. As the objects get closer and closer, the force between them increases. remains constant. decreases.

increases

According to Newton, the greater the distance between gravitationally interacting objects, the more the gravitational force between them. constancy of the force between them. less the gravitational force between them.

less the gravitational force between them.

Compared with the period of satellites in orbit close to Earth, the period of satellites in orbit far from Earth is shorter. the same. longer. not enough information

longer.

From Earth, one satellite appears to overtake another. The faster satellite is lower. higher. can't say

lower.

Each of us weighs a tiny bit less inside the ground floor of a skyscraper than we do on the ground away from the skyscraper because the mass of the building attracts us upward slightly. gravitational force is shielded inside the building. both none of the above

mass of the building attracts us upward slightly.

According to Newton, the closer gravitationally interacting objects are to each other, the constancy of the force between them. more the gravitational force between them. less the gravitational force between them.

more the gravitational force between them.

At some point between Earth and the Moon, the forces due to gravity on a space traveler would be the same. This point is nearer Earth. mid-way between Earth and the Moon. nearer the Moon. none of the above

nearer the Moon.

An Earth satellite is in an elliptical orbit. The satellite travels fastest when it is nearest the Earth. farthest from the Earth. neither

nearest the Earth.

Does your gravitational acceleration depend on your mass? yes no

no

A projectile is fired horizontally. With no air resistance it maintains its horizontal component of velocity because no horizontal forces act on it. no forces act on it. of no initial vertical component of velocity. all of the above none of the above

no forces act on it.

Tangential velocity is velocity parallel to the surface of the Earth. attributed to satellites moving in any direction. perpendicular to the surface of the Earth.

parallel to the surface of the Earth.

The force of gravity acts on all apples on an apple tree. Some apples are twice as far from the ground. Such twice-as-high apples of the same mass, have 1/4 the weight. 1/2 the weight. practically the same weight.

practically the same weight.

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

rise and fall back to Earth's surface.