Ch 4 Test: Gravity and Orbits

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

A. increase

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

A. increase also

A very massive object A and a less massive object B move toward each other because of gravity. As the Objects get closer and closer, the force between them A. increases B. decreases C. remains constant

A. increases

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

A. increases

Suppose the Moon had twice as much mass as it does now and still orbits Earth at the same distance. In that case, the ocean bulges on Earth would be A. larger B. smaller C. unequal in size D. not significantly different E. none of these

A. larger

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

A. less than 8 km/s

According to Newton, the greater the distance between masses of interacting objects, the A. less the gravitational force between them B. more the gravitational force between them

A. less the gravitational force between them

_______ doesn't change with changes in gravity. A. mass B. falling speed C. weight D. terminal speed

A. mass

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

A. nearest the Earth

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

A. parallel to the surface of the Earth

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

B. apparent weight for you

Inside a freely falling runaway elevator, your A. acceleration is zero B. apparent weight is zero C. gravitational interaction with the Earth is zero D. all of these E. none of these

B. apparent weight is zero

The Earth's gravitational field extends A. only above and beyond the Earth's surface and cancels inside the Earth B. both inside and outside the Earth and throughout the entire universe C. neither of these

B. both inside and outside the Earth and throughout the entire universe

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

A. True

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. not at all if air resistance is ignored

A. as soon as it leaves the barrel

Earth satellites are typically more than 100 km high so as to be above the Earth's A. atmosphere B. gravitational field C. both of these

A. atmosphere

A supplier wants to make a profit b boring metal by weight at one altitude and selling it at the same price per pound at another altitude. The supplier should A. buy at a high altitude and sell at a low altitude B. buy at a low altitude and sell at a high altitude C. disregard altitude because it makes no difference

A. buy at a high altitude and sell at a low altitude

A projectile is thrown into the air at an angle of 50 degrees and lands on a target that is at the same level the projectile started. It will also land on the target if it is thrown at an angle of A. 40 degrees B. 45 degrees C. 55 degrees D. 60 degrees E. none of these

A. 40 degrees

A stone is thrown horizontally from the top of a cliff. One second after it has left your hand, its vertical distance below the top of the cliff is A. 5 m B. 10 m C. 15 m

A. 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 A. 5 m below the straight line B. 10 m below the straight line C. 15 m below the straight line

A. 5 m below the straight line

An object is placed exactly halfway between the Earth and moon. The object will fall toward the A. Earth B. Moon C. neither of these

A. Earth

According to the law of gravitation, as the mass of objects increases so does the A. size of the gravitational force pulling them together B. square of the distance between them C. rate of acceleration pulling them together D. size of the gravitational force pushing them apart

A. size of the gravitational force pulling them together

Which is most responsible for the ocean tides? A. the Moon B. the Sun C. both contribute equally

A. the Moon

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

A. their tangential velocities

An object that is in free fall seems to be A. weightless B. slowed by air resistance C. speeded up by air resistance D. not moving

A. weightless

The Earth is closer to the Sun in January then in July, which accounts for the fact that the highest high tides in the northern hemisphere occur in A. winter B. spring C. summer D. no particular time because tides do not depend on seasons

A. winter

With respect to the stars, the Moon A. circles the Earth B. and the Earth circle each other C. remains stationary while the Earth circles about it D. does not rotate about its own axis as the Earth does

B. and the Earth circle each other

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

B. greater the gravitational force between them

The main reason ocean tides exist is that the pull of the moon A. and the sun are in conjunction at high tides and in opposition at low tides B. is greater on oceans closer to the Moon and less on oceans farther from the Moon C. is greater on the Earth because the Moon is closer to Earth D. and the sun on the oceans are in opposite directions E. none of these

B. is greater on oceans closer to the Moon and less on oceans farther from the Moon

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

B. more than 8 km/s

Acceleration is greatest for a satellite when it is at the A. apogee B. perigee C. same at both places

B. perigee

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

B. remains unchanged

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

B. rise and fall back to the Earth's surface

Newton discovered A. gravity B. that gravity is universal C. neither

B. that gravity is universal

A hinter aims a rifle at an angle of 10 degrees above 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 dropped one B. the fired one C. both hit at the same time

B. the fired one

Which produces a greater tidal effect in your body, an overhead Moon, or a grapefruit sitting on your head? A. the Moon, of course B. the grapefruit C. not enough information to estimate

B. the grapefruit

A bullet fired horizontal hits the ground in 0.5 s. If it had been fired with twice the speed in the same direction, it would have hit the ground in A. less than 0.5 s B. more than 05 s C. 0.5 s

C. 0.5 s

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

C. 500N

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

C. always false

If the Sun were twice as massive A. its pull on the Earth would double B. the pull of the Earth on the Sun would double C. both of these D. neither of these

C. both of these

It takes Pluto a longer time to travel around the Sun than the Earth does because Pluto A. has farther to go B. goes slower C. both of these D. none of these

C. both of these

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

C. decreases

If the distance between two objects decreased (i.e. they got closer), then the gravity between the two objects would A. stay the same B. decrease C. increase D. stop entirely

C. increase

If the mass of two objects increased, the gravity between the two objects would A. stay the same B. decrease C. increase D. stop entirely

C. increase

One problem weightlessness can cause for astronauts is __________ (long term) A. freefall B. it changes their mass C. it can weaken muscles and bones D. it keeps them from eating

C. it can weaken muscles and bones

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

C. orbiting Earth with a 24-hour period

If your mass, the mass of the Earth, and the mass of everything in the solar system were twice as much as it is now, yet everything stayed the same size, your weight on Earth would A. be the same B. double C. quadruple D. be eight times as much as now E. none of these

C. quadruple

The fastest moving planet in a solar system is A. the smaller planet B. the most massive planet C. the planet nearest the Sun D. the planet farthest from the Sun E. any planet, for they all move at the same speed

C. the planet nearest the Sun

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

C. the same as it was at the top of its path

A projectile is launched at an angle of 15 degrees above the horizontal and lands downrange. What other projection angle for the same speed would produce the same downrange distance? A. 30 degrees B. 45 degrees C. 50 degrees D. 75 degrees E. 90 degrees

D. 75 degrees

The circular orbit of a satellite orbiting the Earth is characterized by a constant A. speed B. acceleration C. radial distance D. all of these E. none of these

D. all of these

The path of a projectile on Earth is A. straight B. always vertical C. always horizontal D. curved like a parabola

D. curved like a parabola

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

D. like the shuttle, pulled by Earth's gravitation

The amount of gravitational force between objects depends on their A. frictional forces B. speed and direction C. inertia D. masses and the distance between them

D. masses and the distance between them

A satellite in an elliptical orbit travels at constant A. velocity B. speed C. acceleration D. all of these E. none of these

E. none of these

What prevents satellites such as the space shuttle from falling? A. gravity B. centripetal force C. centrifugal force D. the absence of air drag E. nothing, they continually fall around the Earth

E. nothing, they continually fall around the Earth