Rotational Kinetic Energy

Compute rotational kinetic energy E from moment of inertia I and speed n.

Inputs

Formula

E = ½·I·ω², ω = 2πn/60
Flywheel energy storage exploits rotational KE.
rot. KE
Rotational Kinetic Energy schematic

Fundamentals

Compute rotational kinetic energy E from moment of inertia I and speed n.

This tool computes Rotational Kinetic Energy from the formula: E = ½·I·ω², ω = 2πn/60

History

Classical mechanics founded by Newton; kinematics formulas remain the basis of mechanical and vehicle design.

Engineering applications

Used for mechanism kinematics, energy calculations and balancing.

Glossary

Inertia IInput parameter
Speed nInput parameter
Angular speed ωOutput result
Rot. energy EOutput result

How to use

  1. Fill in Inertia I, Speed n in the Inputs section (watch the unit on each field).
  2. Click Calculate; the tool evaluates the formula shown above.
  3. Read Angular speed ω, Rot. energy E in the results area.

Formula · Worked Example · Knowledge

Formula

核心计算关系:E = ½·I·ω², ω = 2πn/60

输入变量:

  • Inertia I I — kg·m²
  • Speed n n — rpm

输出结果:

  • Angular speed ω omega — rad/s
  • Rot. energy E E — J

假设/适用:Kinematic formulas assume rigid bodies, ignoring friction & elasticity; add losses for dynamics.

Worked Example

根据公式 E = ½·I·ω², ω = 2πn/60,取 Inertia I = 0.5 kg·m²;Speed n = 3,000 rpm。

代入计算得:Angular speed ω = 314.2 rad/s;Rot. energy E = 24,670 J。

Key Points

  • Kinematic formulas assume rigid bodies, ignoring friction & elasticity; add losses for dynamics.
  • Use SI units (kg, m, s, rad) to avoid conversion errors.
  • Angular and linear quantities relate by radius r: v = ω·r, a = α·r.

Parameters

Inputs

ParameterSymbolUnitDefault
Inertia I (kg·m²)Ikg·m²0.5
Speed n (rpm)nrpm3000

Outputs

ResultSymbolUnit
Angular speed ωomegarad/s
Rot. energy EEJ

Applications

  • Linkage and cam kinematics design
  • Pulley mechanical-advantage study
  • Engine valve-train and crank analysis

FAQ

What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: E = ½·I·ω², ω = 2πn/60
How accurate are the results?
Results match input precision, based on SI units and common engineering approximations; for critical duty re-check with a safety factor.
Where is it used?
Linkage and cam kinematics design