# The power absorbed by the BOX is

The power absorbed by the BOX is $0.1e^{-4t}$ W. Calculate the energy absorbed by the BOX during this same time interval.

Image from: J. D. Irwin and R. M. Nelms, Basic engineering circuit analysis, 10th ed. Hoboken, NJ: John Wiley, 2011.

#### Solution:

To solve this question, we must remember the following equation:

$\,\displaystyle W=\int^{t_2}_{t_1}p\,dt$

(Where, $W$ is energy, and $p$ is power)

Substitute the power equation:

$\,\displaystyle W=\int^{\infty}_{0}0.1e^{-4t}\,dt$

$W=-0.025e^{-4t}\Big|^{\infty}_{0}$

$W=0.025$ J