Concepts

Mechanical advantage, forces, work, energy

Overview

Various pulleys with different degrees of mechanical advantage (1:1, 1:2, and 1:4) can be used with different masses and a newton scale to perform a quantitative demonstration.

Details

Equipment

• [3] 1-kg mass
• [1] Set of various other masses
• [1] 20-N display scale
• [1] 1:1 pulley
• [1] 1:2 pulley
• [1] 1:4 pulley
• [2] Lab stand
• [1] Long aluminum rod
• [2] 90-degree clamp
• [3] Hook clamp

Classroom Assembly

1. Mount the rod horizontally on the lab stands.
2. Put the hook clamps on the rod.
3. Hang the pulleys from the hooks.
4. Arrange the strings for the appropriate levels of mechanical advantage.
5. Put masses on the pulleys to keep them from shifting around too much.

Important Notes

• Be careful with the apparatus. The strings occasionally slip out of the pulleys.

Script

1. Weigh the 1-kg mass using the scale.
2. Put a 1-kg mass on the 1:1 pulley.
3. Use the scale to measure the force required to lift the 1-kg mass.
4. Repeat for the other pulleys.

Additional Resources