# Sin 85-5

1. Oct 10, 2011

### whoareyou

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

2. Relevant equations

Famous Five

3. The attempt at a solution

To be honest, I don't know where to start. I've picked an approach by trying to find the acceleration (it says that it is constant), but every time I do, the acceleration won't give me the displacement at each given time interval. I've assumed that there was no initial velocity since the machine looks like it just let the rock fall.

2. Oct 10, 2011

### SammyS

Staff Emeritus
Is there a question here?

What is the statement of the problem you're working on?

3. Oct 11, 2011

### whoareyou

I got an equation: Δd = v1Δt + 0.5aΔt2 --> Δd = 20Δt+10Δt2. It gives me the correct answer to the question; the height is 150 NARGS. But I tried it a different way after.

v1 = v2 - aΔt, and v1 is Δd/Δt, but here I get that the initial velocity is 20, but the acceleration is 10. Is this a calculation error ( I don't think so). Why doesn't this method work?

4. Oct 11, 2011

### SammyS

Staff Emeritus
I don't see how you get 10 (Narg/Glug2). The rock goes 30 Nargs in the first Glug; that's an average velocity of 30 (Narg/Glug). During the next Glug the average velocity is 50 (Narg/Glug). So, the acceleration is 20 (Narg/Glug2).

5. Oct 11, 2011

### whoareyou

I don't think I'm understanding correctly ...

How did you get that in the 2nd glug that the average velocity is 50 n/g ? Isn't 80 Nargs divided by 2 glugs 40 ? 0-0

6. Oct 11, 2011

### SammyS

Staff Emeritus
Went from 30 Nargs to 80 Nargs in the 2nd Glug.