# Homework Help: Distance calculated from Energy

1. Dec 8, 2011

2. Dec 8, 2011

### Simon Bridge

Complete the following so the sentences are true:

The particle starts with ________J kinetic energy.
Work done on the particle increases/decreases it's kinetic energy.

Now how is the Work related to the distance the particle travels?

3. Dec 8, 2011

### azncocoluver

The particle starts with 0 J kinetic energy.

Force relates the work to the distance the particle travels.

4. Dec 8, 2011

### Simon Bridge

Doesn't the particle have some initial velocity?

Select "increases" or "decreases" for the second sentence.

5. Dec 8, 2011

### azncocoluver

Well, at x=0, the Force is 2 Newtons but the x is 0, so wouldn't 2N * 0m = 0 J?

Work done on the particle increases it's kinetic energy.

6. Dec 8, 2011

### Simon Bridge

OK - you've forgotten about the initial velocity. When I read part (b) I see this:

(b) if it starts with a velocity of 2m/s in the +x direction, how far will the particle go in that direction before stopping?

Thus - how much kinetic energy is it starting with?

7. Dec 8, 2011

### azncocoluver

Ooh okay, it's 1 J.

8. Dec 8, 2011

### Simon Bridge

No worries - the eye sometimes skips part of a question. Hate it when that happens :)

9. Dec 8, 2011

### azncocoluver

Thanks :] So once I have 1 J, how do I solve for the distance? I added 1 J to the 3 J at x = 4. W = fd so.. 4 J = F d. What would be my F?

10. Dec 8, 2011

### Simon Bridge

You don't need F. Look at your graph. You did it correctly when you thought you started with 0J energy - do the same thing only starting with 1J