1. Pulleys

2. Fixed Pulley:Fixed Pulley:
•Wheel attached to
surface
•Changes the direction of
the applied force
•NO mechanical
advantage – same amount
of force is required

3. Movable PulleyMovable Pulley:
• Pulley moves along the
rope
• Wheel supports the load
• Effort is in the same
direction as movement
• Reduces the forces needed
to move an object

4. http://www.swe.org/iac/LP/pulley_03.html
In the second picture, the weight is held by two ropes instead
of one. That means the weight is split equally between the
two ropes, so each one holds only half the weight.

5. CombinedCombined
(double) Pulley(double) Pulley:
•Has at least two wheels
•The more complex the
pulley, the more the effort
needed to move the
object decreases

6. Pulleys are used to gain
mechanical advantage trading
the amount of rope you have to
pull to lift an object for how
heavy the object can be.

7. http://www.swe.org/iac/LP/pulley_03.html
The more lines of support (ropes) a pulley has, the more mechanical
advantage it has!