sult) were very close which shows that our experiment had results that were practically equal to the experimental value.
PHYSICS 133 EXPERIMENT NO. 4
CONSERVATION OF ENERGY
In this week's lab, we will study the vector nature of force and energy conservation using
a glider on an air track. A vector can be expressed as the sum of its components along a
conveniently chosen coordinate system. In the first part of this experiment, we will study
the component of the gravitational force,
, by using a tilted air track, where
the tilt angle. For an isolated non-dissipative (e.g., frictionless) system, the total
mechanical energy must be conserved. In the second part of the experiment, we will
examine the law of energy conservation by observing the transfer of gravitational
potential energy to kinetic energy.
1 air track,
1 glider with photogate,
1 light sensor,
1 interface box,
1 computer with timing program,
2 wood blocks,
10 and 20 gram masses,
low-friction pulley and thread.
A battery-powered photogate is mounted on the glider. When activated with the
small push-button on the side of the glider, the photogate turns on a bright,
light emitting diode (LED) whenever the picket fence over the air track blocks
the photogate. A light sensor at the end of the air track receives the LED
signals and a timing program in the computer measures and records the time
intervals between successive lightings of the LED. In the first part of the
experiment, we release the glider from rest on a tilted air track. The
of the glider can be measured and the component of
gravitational force along the air track,
, can be obtained. In the
second part, a small mass is attached to the glider via a thread that passes over
a low-friction pulley at the end of a level air track. The small mass is then
released, causing it to accelerate the glider as it falls. The change in the height
of the small mass is measured, as is the velocity of the glider/mass system.
This will allow us to keep track of the kinetic and potential energy as the small
mass falls, enabling us to test for energy conservation.