Question

A Car is moving with an Vo=72km/hr the driver of the car applies the brake and stops in 0.5mins calculate the acceleration.
V=Vo+at

Answer 1

Given : initial velocity (u) = 72 kmph or 72 x 5/18 m/s = 20 m/s

            final velocity (v) = 0

            time interval (t) = 0.5 min = 30 sec

we know for uniformly accelerated problems

  v = u + at

⇒ 0 = 20 + a x 30

⇒ a = - (20/30)

  ∴ a = - 2/3 m/s²

( negative sign indicates deceleration )

Hope this helps you !!    : )