A hook of radius 2m weighs 100kg. It rolls along a horizontal floor so that its centre if mass has a speed of 20cm/s. How much work has to be done to stop it?

Question

Physics

Nyla Fleming

13 April, 13:13

A hook of radius 2m weighs 100kg. It rolls along a horizontal floor so that its centre if mass has a speed of 20cm/s. How much work has to be done to stop it?

+3

Answers (2)

Know the Answer?

Casey · Answer 1

2 J

Explanation:

Work = change in energy

W = ΔKE

W = ½ mv²

W = ½ (100 kg) (0.2 m/s) ²

W = 2 J

Alejandro Sloan · Answer 2

4Nm

Explanation:

Work done is force times distance.

The force is given as mass x (speed) ^2 / raduis. Expressed mathematically we have;

Mv^2/r

Then for the slightest measurable distance r we have: the work done as;

Mv^2/r * r

= Mv^2

= 100 * 0.2 * 0.2 = 4Nm