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e. Make a drawing of the balance in your notebook
to show the positions of the fulcrum, effort and
load and the directions in which the forces are
acting.
8. Move the effort closer to the fulcrum. Balance the load
by changing the amount of the effort force.
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 effort and balancing
the load again. Record the measurements in the
table.
e. Make a sketch of the balance in your notebook to
show the positions of the fulcrum, effort and load
and the directions in which the forces are acting.
10
Education
®
Extension Activity
1. Use gram weights and a ruler to determine the
mathematical relationship involved in balancing the
lever. Balance the lever with gram weights on both
hanging trays. Use the ruler to measure the distances
of the load and the effort from the fulcrum when the
lever is balanced.
The Principle of Levers states that for a lever to be balanced:
Effort x its distance from the fulcrum = Resistance (load) x its distance from the
fulcrum
E x EA = R x RA
Where:
E = Effort force
EA = Length of Effort Arm
For printer friendly versions of the experiments, go to:
or
R = Resistance
RA = Length of Resistance Arm
and enter the code
www.knex.com/instructions
79319.
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