Question

When a body starts from rest, the acceleration of the body after 2 seconds is _______
of its displacement. (half, twice, four times, one-fourth)

TNSCERT Class 9 General Science Ch 6 Motion

Answer 1

half

cuz acceleration=displacement/time

Answer 2

Explanation:

Let s is the displacement of the body. The formula that relates the acceleration, displacement and the velocity is given by :

$s=ut+\dfrac{1}{2}at^2$

The body is at rest initially, u = 0. Put t = 2 sec in above formula as :

$s=0+\dfrac{1}{2}a(2)^2$

$s=2a$

$a=\dfrac{s}{2}$

So, when a body starts from rest, the acceleration of the body after 2 seconds is  half of its displacement. Hence, this is the required solution.