Question

A force $F=5\hat{i}+4\hat{j}$ newton displaces a body through $S=3\hat{i}+4\hat{K}$ meter in 3 s. Find the power.

Answer 1

Given that,

Force $\overrightarrow{F}=5\hat{i}+4\hat{j}$

Displacement $\overrightarrow{s}=3\hat{i}+4\hat{k}$

Time $t=3s$

Now, the work done is

$W=\overrightarrow{F}\cdot \overrightarrow{s}$

$W=(5\hat{i}+4\hat{j}+0\hat{k})\cdot (3\hat{i}+0\hat{j}+4\hat{k})$

$W=15+0+0$

$W=15J$

Now, the power is

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

$P=\frac{15}{3}$

$P=5watt$

Hence, the power is $5watt$