Question

The magnitude of the kinetic energy of a body is ‘k’. what is its kinetic energy if its velocity is doubled?

Answer 1

Step 1: Definition

The kinetic energy of an object is the energy that it possesses due to its motion. The S.I unit of kinetic energy is Joule or $1\mathrm{kg}.{\mathrm{m}}^2.{\mathrm{s}}^{-2}$.

Mathematically, kinetic energy can be represented as,

$\mathrm{KE}=\frac{1}{2}{\mathrm{mv}}^2$

Here,

m is the mass of the body.

v is the velocity of the body.

Step2: Examples of kinetic energy are as follows

1. A vehicle traveling at a very similar speed as a vehicle has more kinetic energy also because the truck's mass seems to be significantly greater than the car's.
2. As liquid seems to have a specific velocity as well as mass, a river moving at a definite pace has kinetic energy.

Step 3: When speed doubles the kinetic energy

If v becomes 2v, then

$$\begin{gathered} \mathrm{KE}=\frac{1}{2}\mathrm{m}{\left(2\mathrm{v}\right)}^2 \\ =4(\frac{1}{2}\mathrm{m}{\mathrm{v}}^2) \\ =4\mathrm{times}\mathrm{initial}\mathrm{KE} \end{gathered}$$

Therefore, when the object's speed doubles, its kinetic energy doubles to four times the initial kinetic energy.