Question

A car moving with a speed of 20 m/s can be stopped by applying brakes, after traveling a distance of 2m. the retardation of the car is ?
a) 50 m/s^2
b) 100 m/s^2
c) 150 m/s^2
d) 200 m/s^2
please answer it ASAP

Answer 1

U=20m/s
V=0
S=2m
retardation =(negative acceleration )
v2-u2=2as
o -400=2×a×2
-400=4×a
a=-400/4
-a=100mps^2
:::retardation =100m/s^2

Answer 2

Hi friend,

We know that ,

V²-u² = 2as.

As it has final velocity zero because brakes are applied.

:- v² = u²+2as.

0= (20)² +2×a×2

4a=-400

a=-100m/s².

As the retardation means negative acceleration the negative sign is omitted.

:- the correct answer is option (b).

Hope this helped you a little!!!