Question

The mass of a body is halved and its speed is doubled. What happens to the kinetic energy of the body?

• A. Doubled
• B. Becomes four times
• C. Becomes eight times
• D. Remains unchanged

Answer 1

The correct option is A Doubled

Let $KE=\frac{1}{2}m{v}^2$
Given $m^1=\frac{1}{2}m$
$V^1=2V$
$K{E}^1=\frac{1}{2}{m}^1(V^1{)}^2$
$=\frac{1}{2}\times \frac{1}{2}m\times (2V{)}^2$
$=\frac{1}{2}\left(2\right)m{v}^2=2KE$
$\therefore$ KE is doubled.