Question

The expression for kinetic energy is

• A. $\left(\frac{1}{3}\right){\mathrm{mv}}^2$
• B. $\left(\frac{1}{2}\right){\mathrm{mv}}^2$
• C. $\left(\frac{1}{2\mathrm{m}}\right){\mathrm{v}}^2$
• D. $\left(\frac{1}{2}\right)\mathrm{mv}$

Answer 1

The correct option is B

$\left(\frac{1}{2}\right){\mathrm{mv}}^2$

Kinetic energy:

1. The energy possessed by an object due to its motion is known as kinetic energy.
2. Kinetic energy is directly proportional to the mass($\mathrm{m}$) of the object and to the square of its velocity$\left(\mathrm{v}\right)$. That is, $\mathrm{K}.\mathrm{E}=\frac{1}{2}{\mathrm{mv}}^2$
3. Kinetic energy does not require direction to define it, so it is a scalar quantity
4. Kinetic energy is measured in units of Joules ($\mathrm{J}$), where$1\mathrm{J}=1\mathrm{kg}{\mathrm{m}}^{-2}{\mathrm{s}}^{-2}$.
5. Kinetic energy is dimensionally represented as $[{\mathrm{M}}^1{\mathrm{L}}^2{\mathrm{T}}^{-2}]$.

Therefore, the expression for kinetic energy is $\mathrm{K}.\mathrm{E}=\frac{1}{2}{\mathrm{mv}}^2$.

Hence, option B is correct.