SAT Subject Physics Practice Question 48: Answer and Explanation
5. An object moves at constant speed in a circular path. True statements about the motion include which of the following?
I. The velocity is constant.
II. The acceleration is constant.
III. The net force on the object is zero since its speed is constant.
A. II only
B. I and III only
C. II and III only
D. I and II only
E. None of the above
Correct Answer: E
Neither the velocity nor the acceleration is constant because the direction of each of these vectors is always changing as the object moves along its circular path. And the net force on the object is not zero because a centripetal force must be acting to provide the necessary centripetal acceleration to maintain the object’s circular motion.