Question
Question: Is momentum energy?...
Is momentum energy?
Solution
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 (ms−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,
ΔtΔp=F
Here, Δp is the change in momentum
Δt is the time interval
F is the force
The energy and the momentum of a body are related as-
K=21mv2⇒K=21(mv)v
Here, K is the kinetic energy
We know that, p=mv in the above equation, substituting given values to get,
K=21pv
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.