An automobile engine develops 100 kilo-watt, when rotating at a speed of 1800 rev./min. The torque developed by it will be:

 The power delivered by the torque $\tau$ exerted on rotating body is given by
$$\begin{gathered} \because \mathrm{P}=\mathrm{\tau \omega } \\ \Rightarrow \mathrm{\tau }=\frac{\mathrm{P}}{\mathrm{\omega }} \\ \text{ Here }\mathrm{P}=100\mathrm{kW}=100,000 \mathrm{W} \\ \Rightarrow \mathrm{\omega }=\left(\frac{1800}{60}\right)\times 2\mathrm{\pi }=60\mathrm{\pi } \mathrm{rad}/\sec , \\ \Rightarrow \tau =\frac{{10}^5}{60\times 3.14}\simeq 531 \mathrm{Nm} \end{gathered}$$