Drawing on simple mathematical models of a
body moving vertically, conduct experiments that determine the velocity
of a projectile.
You have seen two simple models for the motion of a projectile
moving vertically:
Here v is the projectile's velocity in a upward pointing coordinate
system, y is its height from the origin of that coordinate system,
and g is the acceleration of gravity.
Experiment 1: Kinetic Energy Loss
Determine the fraction of kinetic
energy lost when a ball bounces off the floor.
The kinetic energy of a body of mass
m moving with velocity v is
When a tennis ball, say, bounces off a
hard surface, some energy is lost in the collision. Use the models
given above and an experiment of your own design to estimate the
velocity of a ball dropped from your hand just beforeit strikes
the floor and again just after it bounces away from the floor.
What fraction of the ball's kinetic energy is lost during the
collision with the floor? Does the fraction lost vary with the
height from which the ball is dropped? Repeat your experiment
several times at each height and average the results to increase
their reliability.
Which imposes the more severe limit on the accuracy of your
results, the model or the precision of your experimental
apparatus?
Next: Projectile Velocity
Up: Sample Projects
Previous: Damped
pendulum model
Art Heinricher <
heinrich@wpi.edu>
Last modified: Thu Jun 26 12:37:59 EDT 1997