A body starts from rest with an acceleration of 2 m/s². After 5 second, the direction of acceleration reverses again for 5 second. The displacement is

Options

(a) 5 m
(b) 50 m
(c) 55 m
(d) 0 m

Correct Answer:

0 m

Explanation:

Body starts from rest
.·. u = 0, α = 2 m/s², t = 5 sec
S₁ = ut + 1/2 αt² = 0 х 5 + 1/2 х 2 х 5 х 5 = 25 m.
Now when the body reverse its acceleration
so S₂ = 10 х 5 – 1/2 х 2 х 5 х 5 = 50 – 25 = 25 m.
.·. Total distance travelled = 25 + 25 = 50 m.
Note : There is an error in the question. The distance being a scalar, it will be 50 m but displacement being vector, it was come back to the original position. Therefore it is zero.