Physics 111 Lab #4:
Energy
Key Activities:
Energetics of a Bouncing Ball
One activity will involve
analyzing the potential and kinetic energies (Lectures
9, 10,
11)
of a bouncing basketball.
Using a motion detector, the displacement and
potential, kinetic, and total energies of the basketball can be monitored
(see below), illustrating conservation of energy during free fall motion
of the ball, as well as the loss of the basketball's total energy each time
the ball hits the floor.
Energy Loss of a Bouncing Ball
By plotting the basketball's total energy after
each bounce, En, as a function of the number of bounces, n, one
can analyze the energy loss of the bouncing basketball. As shown in the
lower figure, the total energy of the ball decreases roughly exponentially
with the number of bounces, the significance of which will be explored in
this laboratory.
What's happening?
Energetics of
Sliding Motion
The energetics of a cart sliding down a
"frictionless" incline will also be investigated in order to demonstrate
the relationship between potential and translational kinetic energies,
and the conservation of energy in the absence of dissipation (Lectures
9, 10,
11).
Potential Energy
Stored in a Spring
By attaching a spring to the cart so that the
spring is stretched as the cart rolls down the incline (see previous
activity), the interplay between the cart's kinetic energy, the cart's
gravitational potential energy, and the spring's potential energy will
be studied (Lecture 10).
Plot of the gravitational potential energy of the cart
(bottom left), the kinetic energy of the cart (top right), the spring
potential energy (bottom right), and the total energy (top left), as
the cart rolls from the top of the incline (Lecture
10).
What's happening?