PASCO SE-8685 Pulley Demonstration System - Manual (Page 11)

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Pulley Demonstration System
11
Experiment 3: Discovering the Mechanics of a Wheel and Axle
(4-Step Pulley)
1. Have students measure the diameters of the grooves of the pulley. (If
calipers or a meauring tape is not available, see the Specifications in
Appendix A.)
2. Loop string counterclockwise
around the smallest groove of
the 4-step pulley until there is
enough friction for the string to
support a large mass.
3. Choose one of the other
grooves and loop enough
string clockwise until it can
support some mass.
4. Have the students experiment
with the amount of mass that
balances the system.
5. Ask students to calculate the
ratio between the masses and
compare this value to the ratio
of the diameters of the
grooves. Students should find
that the ratio of the diameters
of the grooves is identical to the ratio of the masses.
Equipment required:
Pulley Demonstration System
(SE-8685) Calipers (SF-8711) or measuring
tape (PM-8761)
Figure 3: Setup with Wheel and
Axle