A car with a mass of 1200 kg develops a power of 70 kW. With what speed does

A car with a mass of 1200 kg develops a power of 70 kW. With what speed does the car move if the traction force is equal to 0.5 of the weight of the car.

To find out the speed of the presented car, we apply the formula: P = F * Vx = 0.5 * P * Vx = 0.5 * ma * g * Vx, from where we express: Vx = 2P / (ma * g).

Const: g – acceleration due to gravity (g ≈ 10 m / s2).

Data: P – effective traction force (P = 70 kW = 7 * 10 ^ 4 W); mа is the mass of the presented car (mа = 1200 kg).

Let’s perform the calculation: Vx = 2P / (ma * g) = 2 * 7 * 10 ^ 4 / (1200 * 10) = 11.6 (6) m / s = 42 km / h.

Answer: The presented car must move at a speed of 42 km / h (11.6 (6) m / s).