# Work and energy

1. Mar 23, 2010

### darkmagic

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

Can someone teach me on how to solve this problem? This is a dynamics mechanics problem. I tried everything I know but I cannot really get the answer. Please help ASAP.

2. Relevant equations

3. The attempt at a solution

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2. Mar 23, 2010

### darkmagic

3. Mar 23, 2010

### Staff: Mentor

When you say that you've tried everything that you know, what have you tried? What approaches? Why do you think that the section that this problem is from is titled "Work and Energy"?

BTW, I get a different answer than is shown. Are you sure about those numbers?

4. Mar 23, 2010

### darkmagic

it involves the work-energy equation. the answer is from my teacher.

5. Mar 23, 2010

### Staff: Mentor

So what can you tell us about the relationship between work and energy? How do you think it applies to this problem?

If I understand the problem statement, a train car or whaver coasts up a grade with some initial velocity, and they want to know what the final backward velocity will be after it goes up, stops, and accelerates back down the grade. What kind of energy equations would you use to approach this?

6. Mar 23, 2010

### darkmagic

the equation that involves in that problem is summation of XS=1/2 W/g [v2 - vo2]

7. Mar 23, 2010

### Staff: Mentor

Sorry, you're going to have to define the terms in that equation for me. And in defining the terms in your own words, you might just talk yourself to the solution of the problem...

Well, except that I still think the posted answer has a typo in it....