# Homework Help: Principle of Work and Energy

1. Mar 6, 2013

### aaronfue

1. The problem statement, all variables and given/known data

If the cord is subjected to a constant force of F= 300 and the 16kg smooth collar starts from rest at A, determine the velocity of the collar when it reaches point B. Neglect the size of the pulley.

2. Relevant equations

($\frac{1}{2}$mv12) + $\sum$U1-2 = ($\frac{1}{2}$mv22)

3. The attempt at a solution

I'm stuck and don't know where to start. Initially I was finding the acceleration given the force and mass, but I'm still having trouble. I doubt that is what I need to start.

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2. Mar 6, 2013

### rude man

Your 'relevant equation' is fine but v1 = 0 here. Also, there is another term you need to add: total energy at A + work done by F = total energy at B.

How far does the cord get pulled by the 300N force along the indicated direction? What is the work done thereby?

How much is the potential energy of the collar get raised when it reaches point B?

Use conservation of energy to determine the K.E. at point B.