Question

Car is moving with speed of 40m/s comes to rest after travelling a distance 400 m on applying brakes the acceleration of car is. A. -5m/s b. -2 m/s. C. -4m /s d. -2.5m/s

Answer 1

Answer:

given

v =40 m/s

s=400m

u=0

a=?

v^2=u^2+2as(equation of motion)

substituting the values we get

1600=0+800a

1600=800a

a=1600/800=2

the velocity of the car is decreasing so acceleration is negative

so the answer is-2m/s