SAT Subject Physics Practice Question 572: Answer and Explanation
13. A toy rocket is launched straight up. At the exact top of its flight path, which of the following is true?
A. Its velocity and acceleration are zero.
B. Its velocity is zero and acceleration is 9.8 m/s2.
C. Its velocity is 9.8 m/s and acceleration is 9.8 m/s2.
D. Its velocity is 9.8 m/s and acceleration is zero.
E. Its velocity is 9.8 m/s and displacement is 9.8 m.
Correct Answer: B
The correct answer is (B). The toy rocket achieves zero velocity at the exact top of its flight when it is not moving upward nor is it moving downward. It is constantly accelerated toward the earth while it is in free fall.