Explain the energy changes in a bouncing ball.

In a bouncing ball, energy changes from potential to kinetic and back, with some energy lost as heat due to friction. Understanding the types of energy involved is crucial in physics.

When a ball is held at a certain height, it possesses potential energy due to its position in the gravitational field. This is because work has been done to lift it against the force of gravity. The potential energy is given by the equation PE = mgh, where m is the mass of the ball, g is the acceleration due to gravity, and h is the height above the ground.

As the ball is released, it begins to fall under the force of gravity. The potential energy it had at the top is gradually converted into kinetic energy as it accelerates towards the ground. The kinetic energy, which can be explored further in energy in SHM, is given by the equation KE = 1/2mv^2, where m is the mass of the ball and v is its velocity. At the moment just before the ball hits the ground, all of its potential energy has been converted into kinetic energy.

When the ball hits the ground, it deforms and then reforms, causing it to bounce back up. During this process, some of the kinetic energy is converted back into potential energy as the ball rises. However, not all the kinetic energy is converted back. Some of it is lost as heat due to the friction between the ball and the ground, and the internal friction within the ball as it deforms and reforms. This heat loss can be better understood by studying heat vs temperature. This is why the ball does not bounce back to its original height.

The process then repeats, with the ball falling and bouncing back up again, each time losing some energy as heat, until eventually it comes to rest. This is an example of the law of conservation of energy, which states that energy cannot be created or destroyed, only transferred or transformed from one form to another. In this case, the energy is transferred from potential to kinetic and back, and transformed into heat. Additionally, understanding Newton's third law helps explain the forces at play when the ball makes contact with the ground and bounces back.

IB Physics Tutor Summary: In a bouncing ball, energy shifts from potential (due to its high position) to kinetic (movement energy) and then back again, but not fully, as some energy escapes as heat because of friction. When a ball is dropped, it turns its high-up energy into movement energy, which partly turns back into high-up energy on bouncing, but it loses a bit each time due to heat, eventually stopping.