A car with a mass of 1 ton moves evenly along the bridge at a height of 10 m from the ground.

A car with a mass of 1 ton moves evenly along the bridge at a height of 10 m from the ground. Vehicle speed 54 km / h. Determine the total mechanical energy of the vehicle

The total mechanical energy of a car is equal to the sum of its potential and kinetic energies. Zero level is the surface of the earth.

E = Ek + En.

Ep = m * g * h, where m is the mass of the car (m = 1 t = 1000 kg), g is the acceleration of gravity (we assume g = 10 m / s2), h is the height above the earth’s surface (h = 10 m) …

Ek = m * V² / 2, where V is the vehicle speed (V = 54 km / h = 54 / 3.6 = 15 m / s).

E = Ek + Ep = m * g * h + m * V² / 2 = 1000 * 10 * 10 + 1000 * 152/2 = 212500 J = 212.5 kJ.

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