# The braking force begins to act on a car with a mass of 20 tons, moving at a speed of 54 km / h

The braking force begins to act on a car with a mass of 20 tons, moving at a speed of 54 km / h, and it stops after 120 s. What is the force acting on the carriage?

These tasks: m (the mass of the car under consideration) = 20 t (in SI m = 20 * 10 ^ 3 kg); V0 (the speed of the car before the action of the braking force) = 54 km / h (in SI V0 = 15 m / s); t (braking time) = 120 s.

The braking force acting on the car in question is determined by the formula: Fstorm. = m * a = m * (V -V0) / t.

Let’s make a calculation: Ftorm. = 20 * 10 ^ 3 * (0 – 15) / 120 = -2.5 * 10 ^ 3 N (-2.5 kN).

Answer: The modulus of the braking force acting on the car in question is 2.5 kN.

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