Chapter 22, Problem 51A

a.

To determine

Power delivered to motor.

Answer to Problem 51A

  $P=18\text{W}$

Explanation of Solution

Given:

Applied voltage, $V=12\text{V}$

Circuit current, $I=1.5\text{A}$

Formula Used:

The electrical power is given as,

  $P=VI$

Where, $P$ is electrical power, $V$ is applied voltage and $I$ is current produced.

Calculation:

On substituting the given values in above relation,

  $\begin{array}{c}P=12\times 1.5\\ =18\text{W}\end{array}$

Conclusion:

Therefore, the power delivered to motor is $P=18\text{W}$

b.

To determine

Amount of energy transformed.

Answer to Problem 51A

  $E=1.62\times {10}^4\text{J}$

Explanation of Solution

Given:

Applied voltage, $V=12\text{V}$

Circuit current, $I=1.5\text{A}$

Motor runs for $t=15\text{min}$

Formula used:

The energy power relation is,

  $E=Pt$

Where, $E$ is energy transformed, $P$ is power and $t$ is time.

Calculation:

The value of power $P=18\text{W}$ from subpart (a).

So, on substituting the values

  $\begin{array}{c}E=18\times \left(15\times 60\right)\\ =1.62\times {10}^4\text{J}\end{array}$

Conclusion:

Therefore, the energy transformed in $t=15\text{min}$ is $E=1.62\times {10}^4\text{J}$