A car is going 60.0 mi/h and has to stop in 6.0 seconds. What is the car’s acceleration?

Explanation:

Convert mi/h to ft/s.

60.0 mi/h × (5280 ft/mi) × (1 h / 3600 s) = 88.0 ft/s

Find the acceleration.

a = Δv / Δt

a = (0 ft/s − 88.0 ft/s) / 6.0 s

a = -14.7 ft/s²

The driver must accelerate the car at the average rate of

- 10 mile / hour-second

for 6 seconds .

u=13

v=30

s/t=u+1\2at

=13+431/2

=13+265.5

=278.5