Question

Find the power output of the engine of a 1200 kg car while the car accelerates from

30 km/h to 100 km/h in 10 s. 

Answer 1

Find the work by work-energy theorem:

$$W=E_{K2}-E_{K1}=\frac12mv_2^2-\frac12 mv_1^2=421.3\text{ kJ}.$$

The power output can be found by the following equation:

$$P=\frac Wt=42.13\text{ kW}.$$