Determine the speed with which you need to throw a stone down so that it jumps 5 m above
Determine the speed with which you need to throw a stone down so that it jumps 5 m above the level from which it was thrown.
g = 10 N / kg.
h = 5 m.
V -?
If the loss of mechanical energy during the movement of the stone can be neglected, then to solve this problem we will use the law of conservation of total mechanical energy. At the moment of the throw, the stone has both kinetic Ek0 and potential En0 energy. At the maximum height, the stone will have only the potential energy En.
Ek0 + En0 = En.
Ek = m * V ^ 2/2.
The potential energy En at the maximum height can be represented as the sum: En = En0 + m * g * h.
Ek0 + En0 = En0 + m * g * h.
m * V2 / 2 = m * g * h.
V2 = 2 * g * h.
V = √ (2 * g * h).
V = √ (2 * 10 N / kg * 5 m) = 10 m / s.
Answer: the stone must be thrown at a speed of V = 10 m / s.