Question

The momentum of a particle is found to be numerically equal to its kinetic energy, if all units are expressed in SI, the velocity of the particle must be

• A. 1 m/s
• B. 2 m/s
• C. 3 m/s
• D. 4 m/s

Answer 1

Answer: (B)

2 m/s

Linear momentum is, $P=mv$ and the kinetic energy is $KE=\frac{1}{2}m{v}^2$.
Here, $mv=\frac{1}{2}m{v}^2$

$v^2-2v=0$

or $v(v-2)=0$.

So, either $v=0m/s$ i.e. a trivial case or $v=2m/s$.

So, $v=2m/s$ is the solution.