Physical Science Lab #6

Simple Machines: Levers

Theory

See last lab

Procedure
You will use the lever set up at your bench to measure the following.

1. Hang a mass of 500 or 1000 g (note which) from the hook end of the lever while using the force meter to measure the force required to hold the mass still. Draw a picture of the lever system labeling the effort and resistance forces using the variable names above and use your measurements to find the values of each.
2. What is the mechanical advantage of your machine?
3. Pull the end of the lever with the force meter through a distance of about 10.0cm. Note the distance traveled at this end AND at the end where the mass is hanging.
4. What is the ideal mechanical advantage of your machine? Using your understanding of the geometry of circles (or similar triangles) what relationship do you expect between the amount the lever is puuled at the one end and how far it rises at the other? How is this related to your ideal mechanical advantage?
5. What is the percent efficiency of your machine?
6. Calculate the input and output work for your machine. Use these to calculate the percent efficiency of the machine and compare this to the value found above.