A runner circles a track of radius 150 m in 150 s moving at a constant rate.If the runner was initially moving north,what has been the runner's average acceleration when halfway around the track? A) At a constant rate,the average acceleration would be zero. B) 6.28 m/s²,west C) 0.17 m/s²,south D) No answer is correct. E) 0.17 m/s²,east

Question

Quizplus · Accepted Answer

The runner's average acceleration is given by the change in velocity divided by the time interval in which the change occurred. At the halfway point, the runner is moving horizontally to the east, so the change in velocity is the difference between the initial northward velocity and the final eastward velocity. Since the runner moves half the distance in half the time (i.e. 75 seconds), the average acceleration is (v_f - v_i) / t = (0 - (150 m/150 s)) / 75 s = -2 m/s^2 to the south. However, we need to take the magnitude of the acceleration, so the answer is 2 m/s^2 to the south, or approximately 0.17 m/s^2 to the south.

A Runner Circles a Track of Radius 150 M in 150