Model No. ME-9858
Physical Pendulum Accessory
7
®
Part III: Collecting Velocity Data
Option 1: Measuring the Car’s Velocity with Photogates and a Computer Interface
1.
Place a Photogate on the last peg of the Roller
Coaster track. This will allow you to measure
the speed of the car just before it hits the
pendulum (Figure 6).
2.
Connect the Photogate to a Smart Timer or to
a computer interface (
ScienceWorkshop
or
PASPORT).
Note:
If you are using a PASPORT interface,
first plug the photogate into a PASPORT
Photogate Port; then plug the port into the
computer interface.
3.
Insert the flag into the car (Figure 6). When the car passes through the photogate, the flag
must block the photogate beam. If not, adjust the photogate up and down, so that the flag
blocks the photogate beam. The nuts on the photogate support peg allow the sideways
position of the photogate to also be changed. (For more information, see the Roller
Coaster Manual).
4.
For the Smart Timer, choose speed, one gate, and the velocity will be calculated and
displayed. To use a computer, you will have to use the calculator function and the spacing
on the flag (For instructions, see Appendix A in this manual).
Option 2: Measuring the Car’s Velocity without a Photogate
If you do not have a photogate available, you can estimate the car’s speed using conservation
of energy. By measuring the height of the car above the table both at the top of the hill and at
the bottom, the theoretical speed can be calculated, as follows:
mgh=½mv
2
Note:
The theoretical speed does not depend on the mass of the car.
flag
Figure 6: Car with flag
entering photogate
