Question

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

Answer 1

D. As acceleration is a change of speed or direction.

Answer 2

'Acceleration' means ANY change in speed or direction
of motion.

A). Acceleration. The satellite is in a curved orbit, so
its direction is constantly changing.

B). Acceleration. The person is on a curved track, so
his direction is changing.

C). Acceleration. The car is following a curve, so
its direction is changing.

D). No acceleration. Straight, at constant speed.
No change of speed or direction.