Question

A 1000 kg vehicle moving with a speed of 20 metre per second is brought to rest in a distance of 50 metre.. find the acceleration... calculate the handle is the force acting on the vehicle and the actual force applied by the brakes may be slightly less than that calculated in number.. give reason

Answer 1

Vehical Mass = 1000 kg

Initial Velocity (that is speed) let it be u = 20 ms-1

Final Velocity let it be v= 0ms-1

Distance travelled = 50 m

let the acceleration be "a"

From equation => v2 = u2 + 2as

putting all value

(0m/s)2 = (20m/s)2 + 2*a*50 m

0m2/s2 = 400m2/s2 + 100a m

0m2/s2 - 400m2/s2 = 100a m     (Side changing)

-400m2/s2 = 100a meter

-400m2/s2 / 100 m = a          (side changing and cancelling m with m2)

-4m/s2 = a

a = -4 m/s2

This shows that the acceleration is in opposite direction that means it is retardation.

retardation = 4m/s2

Answer 2

Answer:

i. -4 m/s²

ii. -4000 N

iii. Due to force of friction, which assist in showing down the vehicle, the actual force applied by the brakes may be slightly less than that calculated in (ii).