PASCO ME-6964 PAStrack Wheel Set User Manual
Page 8
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P A S t r a c k w i t h w h e e l s
S u g g e s t e d A c t i v i t i e s
8
relative to the stationary track? How do they move relative to the PAStrack with
wheels?
2.
Incline the stationary track. Place the disk and ring on the PAStrack with wheels
and hold them on the stationary track. Predict what will happen when you release
the disk, ring, and PAStrack with wheels all together.
3.
Release them. How do the disk and ring move relative to each other? How do
they move relative to the stationary track? How do they move relative to the
PAStrack with wheels?
4.
Why does the system behave differently when the acceleration of the PAStrack
with wheels is caused by your hand compared to when the acceleration is caused
by gravity?
Notes and Sample Data
Activity 1: Relative Velocity
In the first run (left),
Vcart
was positive,
Vtrack
was negative, and
Vrel
was equal to their
difference.
When the PAStrack with wheels was held still (center),
Vcart
was equal to
Vrel
from the
original data run.
The direct measurement of
Vrel
made with the sensor attached to the PAStrack with
wheels (right), was also equal to
Vrel
from the first run. Note that the cart was adjusted
to run for slightly less time since it had to start 15 cm away from the sensor.
As shown in this graph (acquired
using two motion sensors), the
distances traveled by the PAS-
track with wheels and the motor-
ized cart are different, but the
center of mass of the cart-track
system remains nearly stationary.
Without the sail, the fan cart moves and the PAStrack with wheels remains stationary.
Unlike in the experiment with the motorized cart, the center of mass of the cart-track
system does not remain constant because this system is not isolated; the fan cart inter-
acts with the air surrounding the apparatus.