Physics

Suppose the gravitational force between two masses is 70N. If the magnitude of one of the masses is halves what is the between the masses? a. 18N b. 280N c. 70N d. 140N e. 30N

e. 30N

a planet has half the mass of the earth and half the radius. Compared to its weight on earth, an apple on this planet would weight ____. a. zero b. half as much c. one-forth as much d. the same e. twice as much

e. twice as much

Suppose the gravitational force between two spheres is 30N. if the magnitude of each mass doubles, what is the force between the masses? a. 120N b. 8N c. 15N d. 30N e. 60N

a. 120N

Suppose the gravitational force between two massive spheres is 100 N. If the distance between the spheres is doubled, what is the force between the masses? a. 25N b. 100N c. 200N d. 400N e. 50N

a. 25N

If the radius of Earth decreased, with no change in mass, your weight would ____. a. increase b. decrease c. not change

a. increase

If you were to weigh yourself in an elevator that is acceleration upward, compared to your ordinary weight you would weigh _____. a. more b. less, but more than zero c. the same d. zero

a. more

The force of gravity on you is greatest when you are standing _____. a. on Earth's surface b. just above Earth's surface c. far above Earth's surface

a. on Earth's surface

if you stood atop a ladder on earth that was as tall as earth's radius (so you were twice as far from earth's center) your weight atop the ladder would be ____. a. one-quarter its normal value b. half its normal value c. one- eight its normal value

a. one-quarter its normal value

Newton reasoned that the gravitational attraction between the Earth and the moon must be _____. a. reduced by distance b. independent of distance c. directly proportional to distance d. the same at all distances

a. reduced by distance

A 560-N woman stands on top of a very tall ladder so she is one earth radius above earth's surface. How much does she weigh? a. 560N b. 140N c. 0 d. 280N

b. 140N

Suppose the gravitational force between two spheres is 70 N. If the distance between the spheres is halved, what is the force between the masses? a. 35N b. 280N c. 140N d. 70N e. 17.5N

b. 280N

Why did Newton think there was a force acting on the moon? a. Because the moon always keeps one side toward the Earth b. Because the moon moves in a curved path c. Because there is no air on the moon d. Because the moon is moving

b. Because the moon moves in a curved path

A very massive object A and a less massive object B move toward each other under the influence of mutual gravitation. Which force, if either, is greater? a. The force on B b. Both forces are the same c. The force on A

b. Both forces are the same

Which is greater, the gravitational force between Earth and the moon, or the force between Earth and the sun? a. equal b. Earth-sun c. Earth-moon

b. Earth-sun

Since Earth is attracted to the sun, why doesn't it fall into the sun? a. because it has too much to move toward the sun b. because it has sufficient tangential velocity c. because there is an equal force holding it away from the sun d. because it has too much inertia to move toward the sun

b. because it has sufficient tangential velocity

if you stand on a weight scale in an elevator that is acceleration upwards, why do you observe an increase in your weight? a. because you are accelerating upwards, you body becomes more massive due to the lower gravity at larger distances from the center of the earth b. because you are accelerating upwards, there is more compression of the springs of the scale. The weight reading on the springs. c. Because you are accelerating upwards, there is less compression of the springs of the scale. The weight reading on the scale reflects the amount of compression of the springs.

b. because you are accelerating upwards, there is more compression of the springs of the scale. The weight reading on the springs.

A supplier wants to make a profit by buying 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 high altitude and sell at a high altitude c. disregard altitude because it has a negligible effect

b. buy at a high altitude and sell at a high altitude

If the Earth's mass decreased to one half its original mass, with no change in the radius, then your weight would___. a. stay the same b. decrease to one half your original weight c. decrease to one quarter you original weight

b. decrease to one half your original weight

Gravitational forces are the weakest forces found in nature. Because of this ____. a. there is no movement between two 1-kg masses located near each other in space b. gravitational forces that are easily observed involve one or more large masses c. gravitational effects occur only when a large mass is involved d. there is no gravitational force between two 1-kg masses e. the gravitational effect between a pencil and Earth cannot be seen

b. gravitational forces that are easily observed involve one or more large masses

Jupiter has more than 300 times the mass of Earth. Yet on Jupiter's surface an object weighs only about 3 times as much as it would on Earth. The explanation to this involves Jupiter's ____. a. high density b. large radius c. greater distance from the sun

b. large radius

Compared to the gravitational field on the surface of earth, the gravitational field well below earth's surface is _____. a. the same b. smaller c. larger

b. smaller

The reason the moon does not fall into Earth is that ____. a. Earth's gravitational field at the moon is weak b. the moon has a sufficiently large orbital speed c. gravitational pull of other planets keeps the moon up d. the moon has less mass than Earth

b. the moon has a sufficiently large orbital speed

Newton had the insight to see that the______. a. moon is moving b. moon orbits Earth c. force on the moon has the same nature as the force on an apple d. moon always keeps one side toward the Earth

c. force on the moon has the same nature as the force on an apple

Two objects move toward each other because of gravitational attraction. As the object gets closer and closer, the force between them ____. a. remains the same b. decrease c. increase

c. increase

If the mass of the Earth increased, with no change in radius, your weight would ____. a. stay the same b. decrease c. increase also

c. increase also

A lunar month is about 28 days. If the moon were closer to Earth than it is now, the lunar month would be ____. a. more than 28 days b. unchanged c. less than 28 days

c. less than 28 days

A hollow spherical planet is habited by people who live inside it, where the gravitational field is zero. When a very massive space ship lands on the planet's surface, the gravitation field inside the planet is ____. a. nonzero, directed away from the spaceship b. still zero c. nonzero, directed toward the spaceship

c. nonzero, directed toward the spaceship

Consider the gravitation force between earth and a meteor in outer space. If the meteor moves so its distance from the earth's center doubles, the gravitational force on the meteor will be ____. a. double b. half c. one quarter d. eight times greater e. quadruple

c. one quarter

If you drop a stone into a hole drilled all the wall to the other side of earth, the stone will ____. a. speed up until it reaches the other side of earth b. stop at the center of earth c. speed up until it gets to the center of earth d. slow down until it reaches the center of earth

c. speed up until it gets to the center of earth

If a weight scale shows that you weigh 200 kg on the surface of the earth, and then you skydive with both of your feet attached to the scale, you will read a weight of... a. 100kg b. 400kg c. 200kg d. 0kg

d. 0kg

If you were to weigh yourself in an elevator that is in free fall, compared to your ordinary weight, you would weight ____. a. more b. the same c. less, but more than zero d. zero

d. zero

the gravitational field strength at the center of earth is ___. a. large b. smaller than the surface but still larger than zero c. the same as on the surface d. zero

d. zero