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100N

A weight watcher who normally weighs 400 N stands on top of a very tall ladder so she is one Earth radius above Earth's surface. How much is her weight there? A) 0 B) 100 N C) 200 N D) 400 N E) none of the above

none of the above

All places on Earth would have high tides at the same instant if the A) Moon did not revolve. B) Moon did not rotate. C) Sun did not revolve. D) Sun did not rotate. E) none of the above

all of the above

An outcome of universal gravitation is that A) planets aren't cubes with sharp corners. B) its discovery prompted other laws of nature. C) prediction and discovery of planets. D) all of the above

increases

As two objects moving toward each other due to gravity get closer, the acceleration of each A) decreases. B) remains constant. C) increases.

remain the same

Earth is presently accelerating toward the Sun (centripetal acceleration). If the Sun collapsed into a black hole, this acceleration would A) increase. B) decrease. C) remain the same. D) cease to exist.

zero

Half-way to the center of a completely hollow planet with a thin uniform shell, your weight would be A) one-quarter of your weight on the surface. B) one-half of your weight on the surface. C) three-quarters of your weight on the surface. D) the same as at the surface. E) zero.

decrease

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

a component of gravitational force parallel to the plane soon acts on it

If a block is set sliding on a huge imaginary frictionless plane in contact with Earth's surface, it will NOT sustain a constant speed because A) a component of gravitational force parallel to the plane soon acts on it. B) gravity gets weaker as distance increases. C) it is not free from the shackles of Earth's gravity. D) of its inertia.

2 tidal bulges

If the Moon were covered with water, tidal effects caused by Earth would find the Moon with A) 1 tidal bulge. B) 2 tidal bulges. C) 3 tidal bulges. D) 4 tidal bulges. E) no tidal bulges.

lower

If the Moon were four times as massive but twice as far from Earth, high tides on Earth would be A) higher. B) lower. C) no different.

the normal force

If you jounce up and down on a bathroom scale, what varies on the scale reading is A) mg. B) the normal force. C) both of these D) neither of these

weight

Inside a freely-falling elevator, you would have no A) gravitational force on you. B) weight. C) both of these D) neither of these

weight is zero

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

both of these

Surrounding a magnet is a magnetic field. Surrounding an electron is an electric field. Surrounding Earth is A) an alteration in space in which mass experiences a force. B) a gravitational field. C) both of these D) neither of these

the constant g

The difference between Newton's law as a proportion and an equation involves A) the constant G. B) the equal sign. C) one being a vector and the other not. D) magnitude and direction.

in the same direction as gravitational attraction

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

stand on a planet with a shrinking radius

The force of gravity acting on you will increase if you A) burrow deep inside Earth. B) stand on a planet with a shrinking radius. C) both of these D) neither of these

none of the above

There would be only one ocean tide per 24-hour day if the A) Earth and Moon were equally massive. B) Moon were more massive than Earth. C) Sun's influence on the tides were negligible. D) Moon's mass were small — only a few kilograms. E) none of the above

all of the above

Tides caused mainly by the Moon occur in Earth's A) oceans. B) atmosphere. C) interior. D) all of the above

none of the above

Two planets in space gravitationally attract each other. If both the masses and distances are doubled, the force between them is A) one-quarter. B) half as much. C) twice as much. D) four times as much. E) none of the above

you, the scale, and earth are in free fall

When you step on a weighing scale at noon, Earth pulls you downward and the overhead Sun pulls you upward. The reason the Sun's pull doesn't decrease your weight at noon is because A) the Sun's pull on you is negligibly small. B) the weighing scale is calibrated only in Earth weight. C) you, the scale, and Earth are in free fall (in orbit) around the Sun. D) the Sun's pull is cancelled by the gravitation of other celestial bodies. E) of tidal effects in the "solid" Earth.

Sun

Which pulls on the oceans of Earth with a greater force? A) Moon B) Sun C) both pull the same.

all of the above

You can experience weight A) standing on Earth's surface. B) in an accelerating elevator away from Earth. C) in a rotating habitat in space. D) all of the above