Question

a bus moving with a speed of 54km/h on applying brakes it stopped in 8 second. calculate the acceleration.​

Answer 1

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

Answer 2

Explanation:

0-54/8

acceleration=8.7m/s^2