- 1). Draw a diagram of a pulley attached to the top of a load and another pulley hanging from a ceiling support. Draw a line threaded over the top pulley, looping under the load-attached pulley, and run it back up to attach to an eyelet underneath the hanging pulley. The line is doubled up between the pulley attached to the load below and the stationary pulley attached above.
- 2). Determine the length of line a workman has to pull out to lift the load 1 meter. If the load has to lift 1 meter, then the attached pulley has to rise 1 meter. Therefore, the two lengths of line between the two pulleys has to shorten 1 meter since the top pulley is stationary. Therefore, the entire length of line must shorten 2 meters.
- 3). Divide the distance of line found in Step 2 by the distance the output work is performed. This gives you your leverage, or mechanical advantage. The leverage for the example above is therefore 2-to-1.
- 4). Divide your load weight by the result in Step 3. This is the line's tension if you hold the load stationary off the ground. (Pulling on the load increases the tension and makes the load rise.) Therefore, if the load is 10 Newtons (the standard scientific unit for force), then 10N/(2/1) = 5N of tension force.
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