Question

Find the work done by car moving
with a velocity
velocity 27 km/h which
stopped alter 2s application of
brakes .Givnen
mass of car 100 kg.
​

Answer 1

Answer:

u= 27

v = 0

t = 2s

(-a) (deceleration) = v-u/t

=> (-a) = -27/2

=> (-a) = -13.5

=> a = 13.5m/s²

note , this 'a' is deceleration hence the minus sign from both the sides r removed.

hence displacement after the application of brakes = ut + ½at²

= 54 + 13.5×4/2

= 54 + 27

= 81m

now force applied by the brakes = ma

= 100×13.5

= 1350N

work done = d×F

= 81 × 1350

= 109350J

= 109.35 kJ

hope it helped :)