A car weighing 2 tons braked and stopped, having covered a distance of 50 m. Find the work of the friction

| May 5, 2021 | education

A car weighing 2 tons braked and stopped, having covered a distance of 50 m. Find the work of the friction force and the change in the kinetic energy of the car if the road is horizontal and the friction coefficient is 0.4.

To find out the work of the friction force acting on the presented car (change in kinetic energy), consider the formula: Atr = ΔEk = -Ftr * S = -μ * ma * g * S, where μ is the coefficient. friction of the wheels of the presented car on the road (μ = 0.4); ma – mass (ma = 2 t = 2 * 10 ^ 3 kg); g – acceleration due to gravity (g ≈ 9.8 m / s2); S – the path traveled to the stop (S = 50 m).

Let’s perform the calculation: Atr = ΔEk = -μ * ma * g * S = -0.4 * 2 * 10 ^ 3 * 9.8 * 50 = -392 * 10 ^ 3 J.

Answer: The work of the friction force and the change in kinetic energy are equal to -392 kJ.



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