A piece of chalk is thrown vertically upward and caught during its descent at the same height from which it was thrown. The position of the chalk is measured from when it left the hand. The positive direction for position, velocity, and acceleration is upward.
What are the signs of the position, velocity, and acceleration during the descending part of the trajectory?
Select an Answer
The correct answer is positive position, negative velocity, and negative acceleration. As the chalk descends, its position is still above the point of release at the hand so it is still positive. The chalk is moving downward so its velocity is now negative. The gravitational force and thus the acceleration are still downward, so the acceleration is still negative.