Question

1. An electric drill operating at 120. volts draws a current of 3.00 amperes. What is the total amount of electrical  energy used by the drill during 30 seconds of operation? 

Answer 1

By definition, the power of drill is

$$P = UI$$

where $U = 120V$ is its operating voltage, $I = 3A$ is its current. The total amount of electrical energy used by the drill during $t = 30s$ is then:

$$W = Pt = UIt$$

Thus, obtain:

$$W = 120V\cdot 3A\cdot 30s = 10800J = 10.8kJ$$

Answer. 10.8 kJ.