1. Pulleys
Vocab

2. Vocab
A Pulley is a wheel with a grooved rim in which a rope can run to change the direction of the pull (force) that lifts a load.

3. A fixed pulley has a wheel that is attached to something above the load.

4. A movable pulley has a wheel that is attached to the load.

5. Mechanical advantage reduces the effort (force) needed to lift a load or overcome a resistance

6. Directional advantage is a change in direction that results from passing a rope through a pulley.

7. PULLEYS
The greater the number of ropes supporting the load, the less effort needed to lift the load.
The effort needed to lift a load can be predicted from the weight of the load and the number of ropes supporting the load.

8. The benefits gained by using simple machines are always balanced by costs. When the benefits outweigh the costs, the machine is a useful tool.
In a pulley system, a reduction in effort is balanced by the distance over which the effort must go. You must pull a further distance, but you use less effort.