a. What happens to the balance? Why does this
happen?
b. What do you need to do to balance the forces in
the model?
5. Go back to your unbalanced model with 2 pulleys on
one side and 1 pulley on the other. Find a different
way to balance the model without adding or removing
pulleys. Tip: Try sliding the hanging trays, one at a
time, closer to the center.
a. What happens?
b. Why does this happen?
6. Copy the table below to record your findings for the
next steps in your notebook.
Effort Arm
Number of
Distance from fulcrum
washers/paperclips (weight)
For printer friendly versions of the experiments, go to:
Load/Resistance Arm
Object
Distance from fulcrum
and enter the code
www.knex.com/instructions
a. Change the balance so that there is one pulley
on each hanging tray. Make sure each tray is the
same distance from the fulcrum. Measure that
distance and record it in the table.
b. Place a small object on the load tray. Use
washers or small paper clips as the weights on
the other tray. Add washers or paper clips to the
effort tray until the balance is level.
c. Count how many washers/paperclips it takes to
balance the balance. Record your result in the
table.
7. Move the load closer to the fulcrum. Balance the load
by changing the amount of the effort force (weight).
a. Record the measurements in the table.
b. What do you notice about the length of the effort
arm and the length of the resistance (load) arm?
c. Did you add or remove weight? Why?
d. Repeat this, moving the load and balancing it
again. Record the measurements in the table.
79319.
9
Education
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