Question

A car with good tires on a dry road can decelerate (slow down) at a steady rate of about 5.0 m/s2 when braking. if a car is initially traveling at 55 mi/h part a how much time does it take the car to stop?

Answer 1

The time required by the car to stop is 4.916 sec.

Since the car is moving with the constant deceleration we can apply the first equation of motion to calculate the time required by the car to stop.

The first equation of motion is given as

V=u+at

Here, V=final speed of the car=0 mi/h as the car stops

u =initial speed of the car=55 mi/hr=24.58 m/s

a= acceleartion =-5 m/s^2 (here negative sign indicates for deceleration)

Now applying the values in the first equation

V=u+at

0=24.58-5*t

t=4.916 sec

Therefore the car will stops in 4.916 sec.