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