When a car runs at a constant speed on a horizontal highway, its power is 80kW and its resistance is 5x10 ^ 3N

When a car runs at a constant speed on a horizontal highway, its power is 80kW and its resistance is 5x10 ^ 3N

W=PT=80000J/SX20S=1600000J

When a heavy truck runs at a constant speed, the power of the engine is 202kw, the speed is 80km / h, and the car runs for 2h, what is the work done by the engine? How much is the traction of the truck?

(1) W = P * t ;
=> W = 202kw * 2h = 202000*7200 J = 1.4544 * 10^9 ;
(2) P = W / t ;
=> P = (F*S) / t = F*(S / t ) = F * v ;
=> F = P / v = 202kw / 80km/h = 202000w / (80 / 3.6)m/s = 9090 N .