Question

A bus decreases its speed from 10m/s to 2m/s in 4 seconds. Its acceleration is,
3 m/s^2 – 2m/s^2 Zero 2 m/s^2

Answer 1

v=u+at , 2=10+a×4 , 2-10=a×4,,, -8=a×4 then a is -8/4 , ,, a= -2 m/sec^2

Answer 2

Question:

A bus decreases its speed from 10m/s to 2m/s in 4 seconds. Its acceleration is,

(A) 3 m/s²

(B) - 2m/s²

(C) Zero

(D) 2 m/s²

Solution:

We will use to the first equation of motion which is,

v = u + at

v = final velocity = 2 m/s

u = initial velocity = 10 m/s

a = acceleration =

t = time = 4 seconds

v = u + at

2 = 10 + a(4)

2 - 10 = 4a

-8 = 4a

a = -8/4

a = -2 m/s²

The acceleration will be of -2 m/s²

(B) - 2m/s² is the correct answer.

The acceleration whose value is in positive means its going forward or accelerating.

The acceleration whose value is in negative means its going backward or deceleration.

In above question bus is decelerating.