A book that weighs 20 N sits on a table. How big and in what direction does the force of gravity from the Earth act on the book? A. 20 N down

B. 20 N up

C. 10 N down

D. 10 N up

Two astronauts are floating in space far away from any planets or stars. What is the direction of the gravitational force that they experience, if any?

2 astronauts floating a few feet apart in space.

A. They do not experience a gravitational force because there is no large object nearby.

B. Away from each other because they are pulled by distant planets and stars.

C. Toward each other, because there is a gravitational force between them.

D. They experience a gravitational force, but its direction cannot be determined.

If the net force acting on a stationary object is zero, then the object will

A. remain at rest.

B. decelerate at a steady rate of speed.

C. begin moving backwards.

D. accelerate in the direction of the strongest force.

A 2 kg cat is stuck in a tree 10 m above the ground. How much GPE does it have?

A. 250 J

B. 20 J

C. 150 J

D. 200 J

Friction typically objects.

A. Slows down

B. Doesn't affect

C. Speeds up

D. Destroys

A toy mouse has a mass of 2 kg and kinetic energy of 25 J. What is its speed?

A. 5 m/s

B. 4 m/s

C. 3 m/s

D. 6 m/s

What was the initial speed of a car if its speed is 40 m/s after 5 seconds of accelerating at -4 m/s2?

A. 25 m/s

B. 20 m/s

C. 50 m/s

D. 60 m/s

Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 km/h to 40 km/h the first second and from 40 km/h to 45 km/h the next second. What is the car’s acceleration?

A. 40 km/h/s

B. 10 km/h/s

C. 5 km/h/s

D. 35 km/h/s

Planets A, B and C are identical. A and C have a giant moon orbiting them, while B has a lightweight artificial satellite orbiting it, as shown in the diagram. Which planet has the strongest gravitational interaction with its satellite?

Planets A, B, and C are all identical. Planet A has a moon orbiting closely to it. Planet B has a small artificial satellite orbiting closely to it. Planet C has a moon orbiting far from it. Planet C

A. Planet A, because its moon is heavy and close to it.

B. Planet C, because it can interact with a heavy object that is far away.

C. Planet B, because only a lightweight object can orbit without falling down.

D. All have the same gravitational attraction, because the planets are all the same mass.

If the mass of an object were to be cut in half, what will happen to its GPE?

A. Not enough info

B. Disappear

C. Halve

D. Double

What is the reaction force for the apple falling to the ground while it is still in the air?

A. Apple pushes down on the ground.

B. Ground pushes up on the apple.

C. Apple pulls up on the Earth.

D. Earth pulls down on the apple.