Question

A ball falls off the desk and hits the floor. Which

situation explains what happens to the kinetic
energy and gravitational potential energy of the
ball as it falls?

Answer 1

A ball falling from a desk loses gravitational potential energy and gains kinetic energy. Upon collision with the floor, some kinetic energy is lost due to deformation, work against the floor, and friction. This loss in kinetic energy is why the ball does not regain its original height.

Step-by-step explanation:

When a ball falls off a desk and hits the floor, its gravitational potential energy is converted into kinetic energy as it falls. This is due to the gravitational force doing positive work as the ball moves in the same direction as the force. When the ball collides with the ground, there is a loss of kinetic energy because:

a. Energy is used to deform the ball's shape during the collision.

b. Energy is lost because the ball does work on the floor during the collision.

c. Friction between the ball and the floor dissipates some energy.

d. Energy is not lost due to work done by gravity because gravitational work only converts the ball's potential energy to kinetic energy, it does not dissipate it.

If the ball only returns to 90% of its original height, it means that some of the energy has been dissipated through the aforementioned mechanisms, primarily deformation and friction, and possibly sound or other forms of energy loss. In this way, not all the kinetic energy that the ball had immediately before the collision is recovered as gravitational potential energy during the rebound, resulting in a lower height.

Answer 2

The potential energy is transformed into kinetic energy

Step-by-step explanation:

This particular case is defined as the principle of energy conservation since energy is not created or destroyed only transforms. When you have potential energy it can be transformed into kinetic energy or vice versa. In this problem, we have the case of a ball that sits on a desk and then falls to the ground. In this way the ground will be taken as a reference point, this is a point at which the potential energy will be equal to zero in such a way that when the ball is on the desktop that is above the reference line its potential energy will be maximum. As the ball drops its potential energy decreases, as the height relative to the ground (reference point) decreases. In contrast its kinetic energy increases and increases as it approaches the ground. So when it hits the ground it will have maximum kinetic energy and will be equal to the potential energy for when the ball was on the desk.

Therefore:

`E_(p) = potential energy [J] = E_(k) = kinetic energy [J]where:\\E_(p) =m*g*h\\m =mass [kg]\\g=gravity[m/s^2]\\h=elevation[m]\\E_(k) = (1)/(2) *m*v^(2) \\where:\\v=velocity [m/s]\\(1)/(2)  *m*v^(2) = m*g*h`