# If an object with a mass of 2 kg  changes speed from 6 m/s to 13 m/s, by how much does its kinetic energy change?

May 1, 2018

$\implies \Delta E = 133 \text{ J}$

#### Explanation:

Kinetic energy is given as:

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

We can compute the change by subtracting the initial from the final energy.

$\Delta E = \frac{1}{2} m {v}_{f}^{2} - \frac{1}{2} m {v}_{i}^{2}$

$\Delta E = \frac{1}{2} m \left({v}_{f}^{2} - {v}_{i}^{2}\right)$

$\Delta E = \frac{1}{2} \left(2\right) \left({\left(13\right)}^{2} - {\left(6\right)}^{2}\right)$

$\Delta E = 169 - 36$

$\implies \Delta E = 133 \text{ J}$