Which of the following has no acceleration
A. A satellite orbiting at a constant speed.
B. A person running once around a track at a constant speed
C. A car making a turn at a constant speed
D. A person running 100 m straight across a field at a constant speed
the answer is D. Acceleration does not depend only in change in speed but also change in direction. Answers A,B and C all involve change in direction of the body. therefore they are accelerating. in D the person is running in straight line at constant speed, so no change in direction and no change in speed.
