When a rock thrown straight upwards gets to the exact top of its path, its
A) velocity is zero and its acceleration is zero.
B) velocity is zero and its acceleration is about 10 meters per second per second.
C) velocity is about 10 m/s and its acceleration is zero.
D) velocity is about 10 m/s and its acceleration is about 10 meters per second per second.
E) none of these
Answer: B