An apple hanging on a branch falls to the ground. What will be the kinetic energy of an apple when it hits
An apple hanging on a branch falls to the ground. What will be the kinetic energy of an apple when it hits the ground, if its initial potential energy is 4.5 J?
Epotential = 4.5 Joules – potential energy of an apple hanging on a tree.
It is required to determine the Ekinetic (Joule) – kinetic energy of the apple at the moment it hits the ground.
When an apple hangs on a tree, its speed and, accordingly, kinetic energy is zero.
This means that the total energy of the apple is equal to the potential energy Epotential = 4.5 Joules. At the moment of hitting the ground, its potential energy is zero (since the distance between the apple and the ground is zero). Then, according to the law of conservation of energy:
Epotential = Ekinetic;
Ekinetic = 4.5 Joules.
Answer: at the moment of hitting the ground, the kinetic energy of the apple is 4.5 Joules.