Civil Engineering PE

Answer: A - The approximate acceleration rate of a vehicle that increases its speed from 55 mph to 65 mph in 15 seconds is 0.98 ft/sec².

Solution: Use the final velocity formula to solve for acceleration

v_f = v_o + at

Where

v_f = 65 mph

v_o = 55 mph

t = 10 seconds

Therefore,

65 mph = 55 mph + a (15 seconds)

[10 mph *(1 hour/3600 seconds)(5280 feet/mile)]/15 seconds = a

a = 0.98 fps/s (feet/sec²)