Kinetic Energy MCQ - Practice Questions with Answers

•  Mechanical Energy-

                 Mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and

                 position of an object.

• Kinetic energy

                 The energy possessed by a body by virtue of its motion is called kinetic energy.

                 E.g-Moving vehicle possesses kinetic energy.

1. The expression for kinetic energy             

$$
K . E .=\frac{1}{2} m v^2
$$

Where $m \rightarrow$ mass
$v \rightarrow$ velocity

       2. Kinetic Energy is always positive.

3.  Kinetic energy depends on the frame of reference -

      The kinetic energy of a person of mass m, sitting in a bus moving with speed v, is zero in the frame of the bus but it is equal to   $\frac{1}{2} m v^2$ in the frame of the earth.

       4. Work-energy theorem-

           Net work done by all the forces acting on a particle is equal to a change in its kinetic energy. 

$\begin{aligned} W & =\frac{1}{2} m v^2-\frac{1}{2} m v_0^2 \\ W & =k_f-k_i \\ \text { Where } m & =\text { mass of the body } \\ v_0 & =\text { initial velocity } \\ v & =\text { final velocity }\end{aligned}$

This theorem is valid for a system in the presence of all types of forces (external or internal, conservative or non-conservative).Í

       5. Relation of kinetic energy with linear momentum

                               k=\frac{m v^2}{2}  ….. (1)

           and, P = mv or  v=p/m ….. (2)

           put this value of v in equation (1)

Put we get $k=\frac{p^2}{2 m}$
Where $p \rightarrow$ momentum

$$
m \rightarrow \text { mass }
$$