Question 1

Suppose you throw a ball vertically into the air. At the exact instant that the ball reaches its highest position, select from the choices below the most accurate description of
-The net external force on the ball.
A) Upward
B) Downward
C) Zero
D) Other (specify)

Accepted Answer

At the highest point, the only force acting on the ball is gravity, which is directed downward. There is no upward force because the ball is momentarily at rest before it starts to fall back down.

Question 2

The diagram below shows a top view of the moon's nearly circular orbit around the earth. The moon orbits the earth at a nearly constant speed.
  
At the point shown, use the arrow choices shown to the right to indicate the direction of
-The moon's velocity.

Accepted Answer