Pulley

By: Olivia Tanner and Kimberly Anderson

What is a pulley?

A wheel with a grooved rim around which a cord passes. It acts to change the direction of a force applied to the cord and is chiefly used (typically in combination) to raise heavy weights.

or

A wheel, with a grooved rim for carrying a line, that turns in a frame or block and serves to change the direction of or to transmit force, as when one end of the line is pulled to raise a weight at the other end.

Mechanical Advantage

It doesn’t decrease the amount of work performed, but it does decrease the amount of effort. It makes things easier to lift and move. The greater the number of pulleys in the system, the less force it will take to lift an object.

Real Life Examples

Example Problem

MA = output force/input force

I have a block and tackle system. I pull down with 200 pounds of force and can lift up to 1,200 pounds with it. What is my mechanical advantage?

MA= 1,200/200

MA= 6