Chapter 4.1, Problem 6PP

To determine

To calculate: the output work from the pulley system.

Answer to Problem 6PP

The output work from the pulley system is $\underset{\_}{63\text{ J}}$ .

Explanation of Solution

Given data:

Input work on the pulley system, $W_{in}=75\text{ J}$

Efficiency of the pulley system, $e=84\%$

Formula used:

Efficiency Equation:

  $e=\frac{W_{out}}{W_{in}}\times 100$

Where $e$ is efficiency of machine (as percentage), $W_{in}$ is the input work in joules and $W_{out}$ is the output work in joules.

Calculation:

As per the problem,

  $\begin{array}{l}{W}_{in}=75\text{ J}\\ e=84\%\end{array}$

Substitute the values of efficiency and input work in the rearranged efficiency equation to get output work:

  $\begin{array}{l}e=\frac{W_{out}}{W_{in}}\times 100\\ W_{out}=\frac{e\times W_{in}}{100}\\ W_{out}=\frac{84\times 75\text{ J}}{100}\\ W_{out}=63\text{ J}\end{array}$

Conclusion:

The output work from the pulley system is $\underset{\_}{63\text{ J}}$ .