A car travels at a constant rate for 100 miles going due west for one hour. Then it travels at a constant rate for another 75 miles west for one hour. What is the instantaneous velocity at any time during the first hour of the trip?

A. 92 mph west

B. 75 mph west

C. 100 mph west

D. 137 mph west

C. 100 mph west

Explanation:

Average velocity is total displacement over total time. During the first hour, the average velocity is:

v_avg = 100 mi / 1 hr

v_avg = 100 mph west

Since the velocity is constant, the instantaneous velocity at any time equals the average velocity.

v = v_avg

v = 100 mph west