A stone weighing 300 g was thrown vertically upward at a speed of 15 m / s.

A stone weighing 300 g was thrown vertically upward at a speed of 15 m / s. What is the kinetic energy of a stone at a height of 2 m? Neglect air resistance.

We consider the condition of the problem and convert the units of measurement to SI systems.

So, we know that the mass of the stone is m = 300 grams = 0.3 kg.

When thrown vertically upwards, the stone gains a speed of 15 m / s. The stone reaches a height equal to h = 2 m. And we are also told that the air resistance can be neglected.

To calculate the kinetic energy, we apply the law of conservation of energy:

Ek = m * v ^ 2/2 + m * g * h.

We need to substitute values in the formula and perform calculations:

Eк = 0.3 * 225/2 + 6 = 39.75 J.