PULLEY WORKSHEET

Physical Science 233
Name _______________________
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PULLEY WORKSHEET
The mechanical advantage for a pulley system can be calculated similarly to the way it was calculated for the
lever.
AMA = R This equation is the same for all simple machines.
E
IMA can be calculated in 2 ways:
1. IMA = ED ED is effort distance. This is the amount of string or rope that is
RD
pulled through a pulley system to raise the resistance.
RD is resistance distance. This is the height that the resistance
has been raised off the ground.
2. The other way to find IMA is to count the number of supporting ropes or strands. See the
example below. This pulley has an IMA of 4. The supporting
strands are numbered.
Example.
below draw a pulley
IMA of 2.
In the space
system with an
Using the information above, answer these questions. Show your work!!
1. George is using a pulley system (called a block and tackle) to lift the engine out of his car. The engine
weighs 10000 Newtons but he only has to use a 400 Newton effort. What is the AMA of this system?
2. George then takes some measurements. He finds that to lift the engine 5 m he had to pull 150 m of rope
through his pulley system. What is the IMA of the system?

3. What causes the difference between AMA and IMA?
4. As you do this problem, ignore friction. If we ignore friction, IMA = AMA. Show your work.
a. What is the IMA of this pulley system?
b. If you want to lift the resistance
2 meters, how much rope would
have to be pulled through
the pulley system?
c. If the resistance is 60 N, what effort
force would be required to lift it?