Question

To avoid an accident, a car decelerates by - 4m/s2 and covers 15 of road until it stops. What was the car’s initial velocity?

Answer 1

Answer: 11m/s

Explanation:

Given,

deacceleration(a) = - 4m/s2

Displacement (s) = 15 m

Car stops i.e. final velocity(v) = 0

Therefore, initial velocity (u) =?

A/Q

v = u + at

u= v - at

u= 0 -(-4 x t)

u= 4t. --------(i)

s = ut + 1/2 at^2

15 = (4t) t + 1/2 (-4) t^2

15 = 4t^2 - 2t^2

15 = 2t^2

t^2 =15/2

t = 2.73861278753 --------(ii)

•• u = 4 x 2.73861278753

u= 10.9544511501

u≈ 11 m/s

According to me it is right.... if this is helpful then let me know and make me brainliest....

Thanks...