What kinetic energy does a 30g rifle bullet have when it is released from the barrel at a speed of 4000m / s?

Given: m (mass of the considered gun bullet) = 30 g (in SI m = 0.03 kg); V (speed of departure from the barrel of the gun) = 4000 m / s.

We calculate the kinetic energy of the considered rifle bullet by the formula: Ek = m * V ^ 2/2.

Let’s calculate: Ek = 0.03 * 4000 ^ 2/2 = 240 * 10 ^ 3 J = 240 kJ.

Answer: The considered rifle bullet has a kinetic energy of 240 kJ (for a rifle bullet an initial velocity of 4000 m / s is unattainable; if its initial velocity is 400 m / s, then the kinetic energy will be 2.4 kJ).