When a rock thrown straight upward gets to the exact top of its path, its velocity is
A)zero and its acceleration is zero.
B)zero and its acceleration is about 10 m/s2.
C)about 10 m/s and its acceleration is zero.
D)about 10 m/s and its acceleration is about 10 m/s2.
E)none of the above

Question

Quizplus · Accepted Answer

At the top of its path, the velocity of the rock is zero because it momentarily stops before starting to fall back down. However, its acceleration is about 10 m/s^2 downward due to gravity, which is constant throughout its flight (ignoring air resistance).

When a Rock Thrown Straight Upward Gets to the Exact