# The tank moves at a speed of 18 km / h, and the truck at a speed of 72 km / h. The mass of the tank is 36 tons.

September 30, 2021 | education

| **The tank moves at a speed of 18 km / h, and the truck at a speed of 72 km / h. The mass of the tank is 36 tons. What is the mass of the truck, if it is known that its momentum is equal to the momentum of the tank.**

Initial data: VT (tank speed) = 18 km / h (5 m / s); Vg (truck speed) = 72 km / h (20 m / s); mt (tank weight) = 36 t (36 * 10 ^ 3 kg); the momentum of the truck is equal to the momentum of the tank.

We determine the mass of the truck from the equality: mt * Vt = mg * Vg, whence mg = mt * Vt / Vg.

Calculation: mg = 36 * 10 ^ 3 * 5/20 = 9 * 10 ^ 3 kg (9 tons).

Answer: The weight of the truck is 9 tons.