Pulley System Calculator — Formula
## Compound Pulley Mechanical Advantage
A pulley system reduces the effort needed to lift a load by distributing the weight across multiple rope segments.
### Formulas
**Ideal MA = number of supporting rope segments (n)**
**Effort = W / (n x efficiency)**
**Rope travel = n x lift distance**
The trade-off is that you must pull n times more rope to lift the load a given distance. Friction in each pulley sheave reduces the actual mechanical advantage.
A pulley system reduces the effort needed to lift a load by distributing the weight across multiple rope segments.
### Formulas
**Ideal MA = number of supporting rope segments (n)**
**Effort = W / (n x efficiency)**
**Rope travel = n x lift distance**
The trade-off is that you must pull n times more rope to lift the load a given distance. Friction in each pulley sheave reduces the actual mechanical advantage.
Exemplo Resolvido
A 4-part block and tackle lifting 1000 N at 90% efficiency.
- Ideal MA = 4
- Ideal effort = 1000 / 4 = 250 N
- Actual effort = 1000 / (4 x 0.9) = 277.8 N
- Rope travel = 4 m of rope per 1 m of lift.