Question

If the speed of a motor car becomes six times, then the kinetic energy becomes

• A. $6$ times
• B. $36$ times
• C. $12$ times
• D. $24$ times

Answer 1

The correct option is B

$36$ times

Explanation

1. The energy which a body possesses by virtue of being in motion is known as Kinetic energy.
2. As we know, the formula of $kineticenergy\left(k\right)=\frac{1}{2}m{v}^2\left(mass=m,velocity=v\right)$.
3. By this formula it is clear that kinetic energy is proportional to the square of the velocity.
4. $K.E.\propto v^2$
5. $K.E.\propto {\left(6\right)}^2$
6. So, If the speed of a motor car becomes $6$ times, then the kinetic energy becomes the square of $6$ that is $36.$

Hence, option (B) is the correct answer.