Question

Pls answer this fast class 9 physics.. ​

Answer 1

$\LARGE{ \underline{ \orange{ \sf{Required \: answer:}}}}$

Here, the force is applied in the upward direction and the body is moving towards right. So, the force and the displacement are perpendicular to each other.

Approach 1:

In this case, the force will not change the speed of the body but only it's direction. As the speed is not changing, there will be no change in the kinetic energy. The work done will be 0 by using work energy theoram.

Approach 2:

We know the formula for finding the work done on the basis of force, displacement and the angle between them.

$\large{ \boxed{ \underline{ \rm{W = Fs \cos( \theta) }}}}$

Here, $\theta$ is the angle subtended by the force applied and the displacement of the object/body. The angle is 90° here. We are known to the value, cos 90° = 0. Hence, W = 0 because cos theta = 0.

• So, Final answer is 0 work done.

Answer 2

$\huge{\underline{\underline{\boxed{\sf{\purple{Answer ࿐}}}}}}$

We know the formula for finding the work done on the basis of force, displacement and the angle between them.

❝ $\small \underline {\sf{W \ = \ F \ scos(θ) }}$❞

• Here, thetaθ is the angle subtended by the force applied and the displacement of the object/body. The angle is 90° here. We are known to the value, cos 90° = 0.

• Hence, W = 0 because cos theta = 0.