Question

What will happen if force is applied on the body in a direction opposite to its direction of motion. Write
an expression for its kinetic energy.

Answer 1

Answer:You need the value to calculate the answer but if we were to consider the force is the same in both sides the motion would halt.Thus, there would be no kinetic energy.

Explanation:

Answer 2

Suppose a body is moving in forward direction with velocity v then if we apply a force which is opposing it then we clearly velocity goes down decreasing .

Expression for kinetic energy would be

$\sf \: k.e = - \dfrac{1}{2} m \vec {v}^{2}$

Negative Sign denotes that Kinetic energy is decreasing when force F is applied on a body and when it comes to rest the K.E would be zero as no velocity is there .

A clear image can be below !

V-> □ <--F

Where a body is moving in forward direction and F is the force which is applied on it!