All Labs

Simple Machines & Mechanical Advantage Lab

Investigate how levers, inclined planes, pulleys, wedges, screws, and wheel-and-axle systems multiply force. Adjust dimensions and friction to see how ideal and actual mechanical advantage change.

Guided Experiment: Comparing Mechanical Advantage Across Machines

How does mechanical advantage differ among the six simple machines? Which machines provide the highest force multiplication, and what is the trade-off?

Write your hypothesis in the Lab Report panel, then click Next.

Diagram

Fulcrum100 NLoad50 NEffortEffort arm: 2 mLoad arm: 1 mClass 1 Lever

Controls

Dimensions
0 (frictionless)0.5 (rough)

Results for Lever (Class 1)

Ideal MAMA=deffortdloadMA = \frac{d_{effort}}{d_{load}}
2
Actual MAMAactual=MAidealtimesetaMA_{actual} = MA_{ideal} \\times \\eta
2
Efficiencyη=WoutWin×100%\eta = \frac{W_{out}}{W_{in}} \times 100\%
100%
Effort ForceFeffort=fracFloadMAactualF_{effort} = \\frac{F_{load}}{MA_{actual}}
50 N
Distance Ratiofracdeffortdload=MAideal\\frac{d_{effort}}{d_{load}} = MA_{ideal}
2
Work (per 1 m load displacement)
Work Output
100 J
Work Input
100 J

Data Table

(0 rows)
#TrialMachineLoad (N)Effort (N)MAEfficiency (%)Dist. Ratio
0 / 500
0 / 500
0 / 500

Reference Guide

Lever & Inclined Plane

A lever multiplies force by the ratio of effort arm to load arm. An inclined plane multiplies force by the ratio of ramp length to height.

MAlever=deffortdload,MAincline=LhMA_{lever} = \frac{d_{effort}}{d_{load}}, \quad MA_{incline} = \frac{L}{h}

Class 1 levers have the fulcrum between effort and load (seesaw). Class 2 levers have the load between fulcrum and effort (wheelbarrow). Class 3 levers have the effort between fulcrum and load (tweezers).

Pulley & Wheel-Axle

A single fixed pulley changes the direction of force without multiplying it (MA = 1). A compound system with multiple supporting ropes multiplies force by the number of rope segments.

MApulley=nropes,MAwheel=RwheelraxleMA_{pulley} = n_{ropes}, \quad MA_{wheel} = \frac{R_{wheel}}{r_{axle}}

A wheel and axle is essentially a rotating lever. Turning the larger wheel requires less force but more distance to lift a load on the axle.

Efficiency & Friction

Friction converts some input work into heat, reducing the actual mechanical advantage below the ideal value.

η=WoutWin×100%,MAactual=MAideal×η100\eta = \frac{W_{out}}{W_{in}} \times 100\%, \quad MA_{actual} = MA_{ideal} \times \frac{\eta}{100}

For an inclined plane, friction depends on the normal force and the angle. For a screw, efficiency drops sharply at small pitch angles because the thread surface area in contact increases.

Work-Energy Principle

Simple machines cannot create energy. In the ideal case, work input equals work output. Force is traded for distance.

Win=Feffort×deffort,Wout=Fload×dloadW_{in} = F_{effort} \times d_{effort}, \quad W_{out} = F_{load} \times d_{load}

When a machine has MA = 4, you need only 1/4 the force but must move the effort through 4 times the distance. With friction, work input always exceeds work output.