Question

You wind a string around the outer rim of a solid disc with a radius of 10.0 cm and a mass of 2.80 kg. The disc sits flat on a frictionless horizontal surface. You pull on the string with a force of 10.0 N for 3.00 s.

Note: In this problem the object is not rolling without slipping, so you cannot use v = ωr or a = αr.

a) What is the final kinetic energy of the disc? This includes both translational and rotational kinetic energy.

b) How far has the disc moved from its starting position in the 3 s?

c) How many revolutions has the disc made in the 3 s?

9a) 482 J 9b) 16.1 m 9c) 51.2 rev

Answer 1