Question

answer it with derivation​

Answer 1

Answer:

Number of revolutions Δθ = ω₀t + 1/2 αt²

ω₀ = 1200 rpm = 1200/60 revolutions per second = 20rps

ω = 1800 rpm = 1800/60 revolutions per second = 30rps

α = (ω-ω₀)/t  = (30-20)/20s = 0.5 revolutions per second²

Δθ = ω₀t + 1/2 αt² = 20(20) + 1/2*(0.5)(20²) = 400 + 100 = 500 revolutions

The motor makes 500 revolutions in 20s