Question

If the velocity of an object is halved the value of kinetic energy will be?

• A. double
• B. become a quarter
• C. halve
• D. remain the same

Answer 1

The correct option is B

become a quarter

We know,

Kinetic energy =$\frac{1}{2}m{v}^2$

According to the question, velocity is halved.

So, New kinetic energy = $\frac{1}{2}m{\left(\frac{v}{2}\right)}^2$

= $\frac{1}{2}m\frac{v^2}{4}$

= $\frac{1}{2}m{v}^2\left(\frac{1}{4}\right)$

Hence, the kinetic energy of the body decreases by $\frac{1}{4}$times, i.e., becomes a quarter.