Chapter 3, Problem 1MC

Which of the following is not a unit of work?

1. a. newton-meter
2. b. joule
3. c. kilogram-meter
4. d. watt-hour

To determine

The unit which is not the unit of work.

Answer to Problem 1MC

Option (c) is not the unit of work.

Explanation of Solution

Formula to calculate work is,

$W=Fd$

Here,

$W$ is the work

$F$ is the force

$d$ is the distance

In SI unit, the unit of work is Joule (J)

Force is Newton (N)

Distance is meter (m)

Thus, the unit of work done is

$\text{Joule}=\text{Newton-meter}$

Formula to calculate power is,

$P=\frac{W}{t}$

Here,

$W$ is the work

$P$ is the power

$t$ is the time

In SI unit, the unit of work is Joule (J)

Power is watt (W)

Time is hour

Thus, the unit of the work is,

$\begin{array}{c}\text{Watt}=\frac{\text{Joule}}{\text{hour}}\\ \text{Joule}=\text{Watt-hour}\end{array}$

Conclusion:

Since, the unit of the work is Joule, newton-meter and watt-hour. Therefore, the kilogram-meter is not the unit of work. Thus, option (c) is correct.

The unit of the work is newton-meter. Thus, option (a) is incorrect.

The unit of the work is Joule. Thus, option (b) is incorrect.

The unit of the work is watt-hour. Thus, option (d) is incorrect.