Question

18. The position x of a particle moving along x-axis at
time (t) is given by the equation t = VX + 2, where
x is in metres and t in seconds. Find the work
done by the force in first four seconds.
(1) Zero
(2) 2 J
(3) 4J.
(4) 8J
10 KE cauired by a mass m in travelling a certain

Answer 1

ANSWER:

(4) 8J

EXPLANATION:

Now to find the work done by force in 4 second, for that we need to find the acceleration of the object in terms of time, t

The formula for the time, t with respect to the distance of the particle is

$t=\sqrt{x}+2$

$x=(t-2)^{2}$

Now after 4 second the distance travelled is x = 4 m

$a=\frac{d^{2} x}{d t^{2}}=2$

Therefore, the acceleration of the object travelling is

$2 m / \mathrm{sec}^{2}$

Therefore, the force of the object  

F=m a=m 2

Therefore, the work done of the object is  

Work = F.S = m2S = 8m Joules