Lyceum A - Physics - Week 19 - Introduction to Pulleys

A pulley is a special type of wheel that has a groove along the center that a rope fits into and a raised rim to prevent the rope from sliding off. A pulley helps us lift objects that might be heavy from one piece to another.

Experiment:

Construct a pulley system with two pulleys. The pulley can be made from an empty thread spool and a coat hanger. Keeping the coat hanger hook at the top, snip off just enough of the rest of the coat hanger that you can insert the ends of the coat hanger into each end of the spool to act as an axle, so the spool spins freely.

Attach the two pulleys across a room at approximately the same height from the floor (on a door knob and a cabinet handle, for example)

Run a long piece of string so that it rolls over both spools.

Before you tie off your long string, slip a small lightweight basket onto the string. Then tie a knot so that it is one continuous loop of string.

You can now place objects in your basket and by pulling on the string, deliver objects in the basket form one location in the room across the room to another location. If there were a huge canyon between these two locations, having a pulley system would cut out all the work of climbing down one canyon wall and up the other canyon wall just to deliver food and supplies.

Try using a system of pulleys to pull items in a basket straight up a distance rather than across a distance. Can you improve upon your system to make it easier to lift up even more weight?

Buy some small pulleys at the hardware store and try this experiment again. Isn’t it nice that you don’t have to make your own pulleys anymore and we can just go out and buy really efficiently made ones?

How to Build a Pulley

https://www.wikihow.com/Build-a-Pulley