# Need a quick check.

1. Oct 5, 2005

### chibi_lenne

These are the questions I've been working on and my physics teacher is away and I just need to have someone look these over before I continue on with the position-time, velocity-time, and acceleration-time graphs that I need to make. (His suggestion) Just to make sure that the information I have currently is accurate, or at the very least leaning in the right direction so I can correct them.
*Please excuse the poor quality of the scans*

2. Oct 5, 2005

### Staff: Mentor

(a) You go from $v = \Delta d / \Delta t$ (correct!) to $\Delta t = v \Delta d$ (incorrect!)
(b) OK
(c) The average speed is $\Delta d / \Delta t$; what's the average speed?
(d) Use $\Delta d = v \Delta t$--you made an error similar to what you did in part a. (And don't confuse speed $v$ with change of speed $\Delta v$.)

3. Oct 5, 2005

### cscott

You need to use equations for uniform acceleration ($v_2^2 = v_1^2 + 2ad$ or $d = v_1t + \frac{1}{2}at^2$) for (c) and time should be 5s for (d) since it's only asking the distance past the hill.

Last edited: Oct 5, 2005
4. Oct 10, 2005

### chibi_lenne

5. Oct 10, 2005