Force Ratio

Overview

Engineering reference data for Force Ratio in mechanics.

Key Formulas

Newton's Second Law

$F = ma$

Force = mass × acceleration.

Work

$W = Fd\cos\theta$

Work = force × displacement × cos(angle).

Kinetic Energy

$E_k = \frac{1}{2}mv^2$

Energy of motion.

Potential Energy

$E_p = mgh$

Gravitational potential energy.

Variables

Machine Examples

Common types of simple machines include:

• Pulley systems
• Gear systems
• Screw-jacks

Example Calculation: Pulley System

Consider a pulley system with 4 supporting ropes and no friction loss ($\mu = 1$). For a load of $100\ \text{kg}$, the effort force $S$ required is $245\ \text{N}$.

The force ratio (mechanical advantage) can be calculated as: $Fr = \frac{F}{S} = \frac{m \cdot g}{S} = \frac{100\ \text{kg} \times 9.81\ \text{m/s}^2}{245\ \text{N}} = 4$

This result indicates the machine multiplies the input effort force by a factor of 4.

References

• Original Source