Scivra
Pro 🔒~12 min

Simple Machines

Levers, pulleys, and inclined planes — making work easier

How it works

Simple machines are devices that make work easier by changing the force needed or the direction of force. There are six types: lever (a rigid bar pivoting on a fulcrum), pulley (a wheel with a rope), inclined plane (a ramp), wheel and axle (a large and small wheel together), wedge (two inclined planes), and screw (an inclined plane wrapped in a spiral). Mechanical advantage (MA) tells you how much a machine multiplies your force. MA > 1 means less force required (but more distance traveled). Work = Force × Distance; simple machines cannot create energy, they only redistribute it. W_in = W_out (in an ideal machine without friction).

Upgrade to Pro to access this experiment

Step-by-step

  1. Select a machine type and adjust the arm lengths (for the lever) or other parameters.
  2. Watch the MA calculation update.
  3. Try lifting a heavy load with and without the machine — see how much less force the machine requires.
  4. Remember: you always have to move a greater distance when using less force!

Key formulas

  • MA=Load ForceEffort Force=deffortdloadMA = \frac{\text{Load Force}}{\text{Effort Force}} = \frac{d_{\text{effort}}}{d_{\text{load}}}Mechanical Advantage — how much the machine multiplies your force
  • W=F×d(work is conserved, never created)W = F \times d \quad (\text{work is conserved, never created})Work in = Work out (ignoring friction). Less force = more distance.

Frequently asked questions

A lever has an effort arm of 3 m and load arm of 1 m. What is the mechanical advantage?
MA = effort arm / load arm = 3/1 = 3. You only need 1/3 of the force, but you push 3× farther.
If a pulley system has MA=4, how much force is needed to lift a 200 N weight?
MA = Load/Effort → Effort = Load/MA = 200/4 = 50 N. But you pull the rope 4× farther than the weight moves.
Name an example of each: lever, pulley, inclined plane in real life.
Lever: seesaw, scissors, bottle opener. Pulley: flagpole, crane, window blinds. Inclined plane: ramp, staircase, slide.
A ramp (inclined plane) is 5 m long and raises a load 1 m high. What is the MA, and how much force is needed to push a 300 N box up the ramp?
MA = length/height = 5/1 = 5. Effort = 300/5 = 60 N (ignoring friction).