Question

The velocity of a body moving in a straight line is increased by applying a
constant force F for some distance in the direction of the motion. The increase in the kinetic energy of the body is equal to

• A. the potential energy of the body.
• B. the work done by the force on the body.
• C. the momentum of the body.
• D. the torque on the body.

Answer 1

The correct option is B the work done by the force on the body.

$v^2-u^2=2$ a.s
This gives $s=\frac{v^2-u^2}{2a}$
$F=ma$
we can write work done (W) by this force F as
$W=ma\left(\frac{v^2-u^2}{2a}\right)=\frac{1}{2}m{v}^2-\frac{1}{2}m{u}^2=(K.E{)}_1$