A car is accelerating when it is:.
(a) traveling on a straight, flat road at 50 miles per hour.
(b) traveling on a straight uphill road at 30 miles per hour. (c) going around a circular track at a steady 100 miles per hour.

A car is accelerating when it is traveling on a straight uphill road at 30 miles per hour.

Explanation:

Acceleration is the change in velocity of an object with respect to time. For a body to accelerate, its velocity must be changing at every time interval. According to option a and c, the velocity of the body is constant during the journey but the time is changing. A body with constant velocity possesses a zero acceleration.

A car travelling on a straight up hill possesses velocity change at each time interval. Since the car is on a slope, its shows its acceleration is changing.

a is the best answer your welcome