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How do I calculate mechanical power in dynamic systems?

GeneralClass 12AllAnswered 27 Mar 2026
Answer

Dynamic systems involve changing motion, requiring consideration of acceleration and forces:

For rotational systems:P = τ × ω

  • τ = torque (N·m)
  • ω = angular velocity (rad/s)

For linear motion with changing velocity:P = F × v

  • F = force applied (N)
  • v = instantaneous velocity (m/s)

For systems with acceleration:Average Power = ΔKE / Δt = [½m(v₂² - v₁²)] / t

Real-world example - Car engine:

  • Engine produces 200 N·m torque at 3,000 RPM
  • Convert RPM to rad/s: ω = (3,000 × 2π) / 60 = 314.16 rad/s
  • Power = 200 × 314.16 = 62,832W ≈ 63 kW ≈ 84 horsepower
General · Class 12