Question

Is momentum energy?

Answer 1

Hint: The product of mass and velocity is momentum. It is the property of a moving body under the action of external forces. While energy is the ability of a body to do work, energy is possessed by a body by virtue of its motion or position. Momentum is a vector quantity but energy is a scalar quantity.

Complete answer:
The product of mass and velocity is momentum. It is a vector quantity. Its SI unit is metre per second ($m{{s}^{-1}}$). Therefore,
$p=mv$
Here, $p$ is the momentum
$m$ is the mass
$v$ is the velocity
Momentum is a property of the motion of a body and is not energy. The ability of a body to do work is the energy possessed by it. Energy is possessed by a body due to its motion or position while momentum is only due to the motion of a body. Also, energy is a scalar quantity and its unit is joules (J)
The rate of change of momentum is the force acting on a body,
$\dfrac{\Delta p}{\Delta t}=F$
Here, $\Delta p$ is the change in momentum
$\Delta t$ is the time interval
$F$ is the force
The energy and the momentum of a body are related as-
$\begin{align}
  & K=\dfrac{1}{2}m{{v}^{2}} \\
 & \Rightarrow K=\dfrac{1}{2}(mv)v \\
\end{align}$
Here, $K$ is the kinetic energy
We know that, $p=mv$ in the above equation, substituting given values to get,
$K=\dfrac{1}{2}pv$
Therefore, momentum is a property of a body due to its motion and is not energy.

Note:
As the momentum remains constant with time, the force is hence, the momentum is conserved when no force is acting on a body. In rotational motion, the angular momentum is analogous to linear momentum. The direction of momentum is the same as the direction of velocity.