Question

A ceiling fan having a moment of inertia 2 kg-m² attains its maximum frequency of 60 rpm in ‘2π’ seconds. Calculate its power rating.

Answer 1

ω₀ = 0, ω = 2πn = 2π × 2 = 4π rad/s

α = `(ω - ω_0)/t`

= `(4π - 0)/(2π)`

= 2 rad/s²

∴ p = τ .ω = I α .ω = 2 × 2 × 4π

= 16π watt ≅ 50 watt