Question

A car a moving at rate of 72km/h and applies brakes which provide a retardation of 5ms-2.
How much time does the car takes to stop.​

Answer 1

Answer:

It needs 4 s to stop the car.

Explanation:

You need to convert first 72 km/h to m/s.

Converting 72 km/h to m/s

72 km/h = 72000 m / 3600 s

72 km/h = 720/36 m/s

72 km/h = 20m/s

Next step is to solve for the needed time to stop the car using t = v / a

t = v / a

t = 20 m/s / 5 m/s^2

t= 20/5 s

t = 4 s

It needs 4 s to stop the car.