Chapter 9, Problem 36A

Calculate the watts of power expended when a force of 1 N moves a book 2 m in a time interval of 1 s.

To determine

Power in watts.

Answer to Problem 36A

Power is equal to, $P=2\text{ W}$

Explanation of Solution

Given :

Force is given, $F=1\text{ N}$

Distance moved by applying force, $s=2\text{ m}$

Time interval is given, $t=1\text{ s}$

Formula used :

  $W=Fs$ …..(1)

Where, W is work done, F is force and s is distance.

  $P=\frac{W}{t}$ …….(2)

Where, W is work done, P is power and t is time.

Calculation :

Now, substituting the value of F and s in equation (1) and solve.

  $\begin{array}{l}W=1\times 2\\ =2\text{ J}\end{array}$

Now, substituting the value of W and t in equation (2) and solve.

  $\begin{array}{l}P=\frac{2}{1}\\ =2\text{ W}\end{array}$

Conclusion :

Therefore, power will be equal to 2 W.