Question

A flywheel of mass 10 kg and diameter 0.4 m rotating at 1:20 rpm has its speed increased to 720 rpm in 8 seconds

Answer 1

Hey dear,
You gave incomplete question.

● Complete question should be -
Q. A flywheel of mass 10 kg and diameter 0.4 m rotating at 120 rpm has its speed increased to 720 rpm in 8 seconds. Find the torque applied.

● Answer -
τ = 3.142 Nm

● Explanation -
# Given-
m = 10 kg
r = 0.2 m
f1 = 120 rpm = 2 Hz
f2 = 720 rpm = 12 Hz
t = 8 s

# Solution -
Moment of inertia of flywheel -
I = mr^2
I = 10 × (0.2)^2
I = 0.4 kgm^2

Angular acceleration is -
α = 2π (f2-f1) / t
α = 2π (12-2) / 8
α = 7.854 rad/s^2

Torque applied is calculated by-
τ = Iα
τ = 0.4 × 7.854
τ = 3.142 Nm

Therefore, torque applied is 3.142 Nm.

Hope this helps you...