In: Physics
A rope of negligible mass is wound around a hollow cylinder of mass 3 kg and radius 40 cm. What is the angular acceleration of the cylinder if the rope is pulled with a force of 30 N? What is the linear acceleration of the rope? Assume that there is no slipping.
Mass of the hollow cylinder, m = 3 kg
Radius of the hollow cylinder, r = 40cm = 0.4 m
Force applied, F = 30 N
Moment of inertia of the hollow cylinder about its axis:
I = mr2
= 3 × (0.4)2 = 0.48 kg m2
Torque, T = F × r = 30 × 0.4 = 12 Nm
Also, we know that :
Torque = moment of inertia x acceleration
T = Iα
( a ) Therefore, α = T / I = 12 / 0.48 = 25 rad s-2
( b ) Linear acceleration = Rα = 0.4 × 25 = 10 m s–2
Angular acceleration is \( 25 rad/s^{2} \) and linear acceleration is \( 10 m/s^{2} \)