Question

The speed-time graph of a car is given below. The car weighs 1000 kg. calculate the braking force applied at the end of 5 s to bring the car to a stop within 1 s.​

Answer 1

Explanation:

Here mass of car m=1000kg

distance s=?

In the first two seconds the speed time graph is OA.

s= area of ΔOAE

=base×height2=OE×EA2

s=2×152=15m

(ii) Initial speed u=15ms−1

final speed v=0

time taken t=1s

braking force F=?

As F=ma=m(v−u)t,F=100(0−15)1

F=−15000N

Negative sign is for opposing force.