Question

A bus moving with a speed of 54 km/h . on applying brakes, it stopped in 8s .calculate the acceleration and the distance travelled in this time

Answer 1

Answer:

Answer:

      Initial Speed  (u)= 54 km /hr = 54 *1000 m / 3600 s = 54*5/18 = 15 m/s

        ( 1km = 1000 m and 1hr = 60 mins = 60*60 seconds = 3600 seconds)

       Time = 8 seconds

      Final Velocity (V) = 0

 we know that ,

        v = u + at

        0 = 15 + a*8

      0 = 15 + 8a

      a= -15/8 m/s²

  Therefore , acceleration is -15/8 m/s²

also ,

          S = ut+1/2at²

          S = 15*8² + 1/2 *(-15/8)*8²

             =15*64 - 15*4

            = 15(64 - 4)

            =15(60)

            S=900 m

hence Stopping Distance traveled before stopping is 900m .