A uniform disk of radius 0.2 m and mass m = 16 kg is mounted on a nearly frictionless axle. A string is wrapped tightly around the disk and pulled with a constant force of F = 1 N. After a while the disk has reached an angular speed of!0 = 1.2 rad/s. What is its angular speed 1.5 s later?

0.684 rad/s

Explanation:

The moment of inertia of a uniform disk is assumed = 0.5MR² where m is mass and R is radius

I, moment of inertia = 0.5 * 16 * (0.2 m) ² = 0.32 kgm²

Torque of the force = F * R = 1 * 0.2 = 0.2 Nm

angular speed = moment of inertia I * angular speed ω

new angular speed = Iω + (Torque * time) = (0.32 kgm² * 1.2rad/s) + (0.2 Nm * 1.5 s) = 0.684 rad/s