Question

The kinetic energy of a moving cart when its mass is doubled and speed remains the same.

• A. is doubled
• B. is quadrupled
• C. is same

Answer 1

The correct option is A is doubled

The kinetic energy of a moving body is given by:
$KE=\frac{1}{2}m{v}^2$
where:
m - Mass of the body
v - Speed of the body.

If mass $m$ is doubled, new mass is given by:
$m^{\prime }=2m$
Speed is kept the same.
New kinetic energy is given by:
$K{E}^{\prime }=\frac{1}{2}{m}^{\prime }{v}^2$
$K{E}^{\prime }=\frac{1}{2}\left(2m\right)v^2$
$K{E}^{\prime }=2KE$

Hence, kinetic energy is doubled.