Pulleys

1. Who invented pulleys and when?The origin of pulleys is not known, but some believe that pulley were first invented about 1400 BC.
2. What can pulleys be made out of? Pulleys are a simple machine that is made with a wheel on  an axle and a rope, pulley that we use in our lives  are  normally made out of medal and a rope, chain or a cable.But can be made out almost anything your heart desires.
3. In everyday life where do pulleys occur most? Elevators use an electric pulley system to make the  elevator move. Exercise machines, most exercise  machines that lift weights pulleys help put the  rope on the right angle. Bowling alleys use an electric pulley system for the ball to be  collected and brought back up to where you are  bowling from. Flag poles use a pulley on both ends and  you can pull up the flag and down. Sails on boats, boat sails use a for pulley getting the sail up and down and because some of the sails are so big and you would struggle without pulleys.
4. If you have two pulleys is it easier to lift a load than with one pulley?Yes, the more pulleys you add the more weight you can lift easily.

4. ½ But how?

By a purchase system.

4. ¾ What’s a purchase system?

This is a purchase system:

A purchase system is when there are more than one pulley working to lift the load. This is a two by one purchase system.

5. How do pulleys work?

The load is attached to the rope and then the rope goes through a pulley then the rope comes back down to you a you will pull to lift the load:

6. How many pulleys are needed to lift a 100 kg load and make the effort 25 kg?

Four pulleys are needed to make the weight of 100kgs to 25kgs.