Vernier Software and Technology
Vernier Software & Technology


Figure from experiment 5 from STEM 2 with Vernier and LEGO® MINDSTORMS® NXT


A pulley is a simple machine used to change the magnitude and/or direction of an effort (applied) force required to lift a load. It consists of a rope that passes over a grooved wheel. There are three basic types of pulleys: fixed, movable, and compound. A fixed pulley is attached to a solid support with one end of the rope attached to the load. A force equal to the load is applied in one direction to make the load move in the opposite direction.

A movable pulley is attached to the load, and one end of the rope is attached to a solid support. A force equal to only half the load is required to lift it, but the rope must be pulled twice as far as the load is raised. A compound pulley uses more than one pulley. The rope is attached to the innermost pulley and wound around subsequent pulleys in a spiral configuration. The more pulleys used, the less force required to lift the load. Mechanical advantage (MA) is a value that tells the number of times a pulley increases your applied force. In this activity, you will use a Force Sensor to measure the effort force for three different pulley systems, and then determine the mechanical advantage of each system.


In this experiment, you will.

  • Use a Force Sensor and NXT to measure the effort force when using a pulley.
  • Calculate actual mechanical advantage and ideal mechanical advantage.
  • Determine efficiency.
  • Make conclusions about pulley systems.

Sensors and Equipment

This project/activity features the following Vernier sensors and equipment.

Additional Requirements

You will also need NXT Sensor Adapter and a LEGO MINDSTORMS NXT robotics system.

STEM 2 with Vernier and LEGO® MINDSTORMS® NXT

See other experiments from the lab book.

2First-Class Levers
3Audio Assistant
6String Tension Tester
7Gas Pressure
8Yeast in Action
9Grip Strength
10Cartesian Diver
12Lemon Battery
13Battery Tester
14Solar Cells
15Solar Tracker
16Mapping a Magnetic Field
18Migrating Robot
19Magnet Finder
20Mine Sweeper

Project/activity 5 from STEM 2 with Vernier and LEGO® MINDSTORMS® NXT Lab Book

<em>STEM 2 with Vernier and LEGO<sup>®</sup> MINDSTORMS<sup>®</sup> NXT</em> book cover

Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.

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