Question

A car is speeding along a level road at 25 m/s. The brakes abruptly bring the500 kg car to a speed of 3 m/s over a distance of 5 m. Determine the force applied by
brakes and the work done by the car on the brakes.

Answer 1

a=v^2-u^/2s
=(3)2-(25)2/10
-61.6m/s^2
f=ma
500*-61.6
-30800 N
wd =fs
30800*5
-154000j
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Answer 2

Answer:

u = 25m/s

v = 3m/s

distance(s) = 5 m

a = v^2-u^2/2s

= 3^2-25^2/2*5

-61.6m/s

F = ma

= 500*-61.6

= -30800N

W = Fs

= -30800*5

= -154000J