Forest PHYS100 Demos Week6
Bowling Ball Pendulum:
First describe how you do work to position the ball up to your nose and that the work you do is converted to potential energy. For this demonstration I will hold a bowling ball pendulum up to my nose and release it. Before I do this, I will ask the students if the bowling ball will hit me in the face or touch my nose again. The answer is that energy is conserved in this system so the bowling ball should return to its original height. I could include that you must do work in order for the ball to rise any higher.
High Road Low Road:
For this demonstration I will ask the students what they expect to happen in terms of energy on each part of each track. There are some parts of the track where the potential energy is converted into kinetic and rotational energy, but overall energy is conserved so the balls come to the end of the track with the same final velocity at the same time.
Ball in a Loop:
Ask the student to calculate the height required so the car makes it through the loop-de-loop
For this I will basically run through the required calculation to find the minimum height that the ball will have to be placed at in order to make the loop. We can find the minimum velocity at the top of the loop by setting mg = mv^2/r, then we can take that velocity and conserve energy to find the height that the ball must be dropped from.
Poppers:
Conservation of energy implies that if I drop something, it should not be able to bounce higher than the original distance that it was dropped from. Using a popper I will drop it on the ground and it will fly higher than I dropped it from. The reason is because I gave the popper some potential energy in order for it to bounce higher.
Pendulum Calculation:
For this demonstration I will tell the students that I will release a pendulum from a certain height and I want them to calculate the velocity at the bottom of the arc. Simply conserve energy and show the students the results using a photogate.
Let the students measure the speed at the bottom of the swing. Can each student use a different mass ball?