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Mass from force
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Calculators / Science / Two-mass ideal pulley
Two-mass ideal pulley calculator
Calculate acceleration and tension for two hanging masses joined over an ideal pulley.
On this page
Acceleration toward mass 21.96m/s²
String tension23.54N
Calculator controls
How to calculate
Calculate acceleration and tension for two hanging masses joined over an ideal pulley.
Acceleration toward mass 2 =
(m2-m1)*g/(m1+m2) m/s²String tension =
2*m1*m2*g/(m1+m2) NWorked example
- First hanging mass (kg): 2
- Second hanging mass (kg): 3
- Gravity (m/s²): 9.80665
- Acceleration toward mass 2: 1.96 m/s²
- String tension: 23.54 N
Assumptions and limits
This is an ideal educational model. Enter quantities in the stated SI units; it does not certify equipment safety or real operating limits. The string is massless and inextensible; the pulley is frictionless and has negligible rotational inertia.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Calculate acceleration and tension for two hanging masses joined over an ideal pulley. A negative acceleration means mass 1 moves downward. Equal masses give zero acceleration, not zero tension.
When this tool is useful
A negative acceleration means mass 1 moves downward. Equal masses give zero acceleration, not zero tension.
Understanding your inputs
| Input | Example |
|---|---|
First hanging mass (kg) m1 | 2 |
Second hanging mass (kg) m2 | 3 |
Gravity (m/s²) g | 9.80665 |
Frequently asked questions
Which assumptions matter for this result?
This is an ideal educational model. Enter quantities in the stated SI units; it does not certify equipment safety or real operating limits. The string is massless and inextensible; the pulley is frictionless and has negligible rotational inertia.
How can I check the worked example?
Use the displayed example inputs in the stated formula. Keep each quantity in its labelled unit and compare the unrounded result before applying display rounding.