# Velecity of a galloping horse

1. Jan 31, 2012

### chinnie15

Hello,

I am new to physics and am having trouble with this homework problem. I thought I understood it, but it told me I was wrong and I'm not quite sure why. Here is the motion diagram I was given in the homework for the problem:

The question is: What is the horse's velocity during the first ten seconds of its gallop?

Seems easy enough?

I know v=Δx/Δt, and Δx= xf-xi, and Δt= tf-ti

So, from that I am figuring that the x on the diagram starts at 700m. At 10 seconds, the displacement would be 500-700= -200. The time would be 10 seconds (since it's going from 0s to 10s). Then, the velocity would equal -20m/s. But, the program is telling me that I am incorrect. Am I just reading/interpreting something wrong here? I think I understand, generally, what I'm supposed to be doing?

Thank you so much for any help on this!

2. Jan 31, 2012

### HallsofIvy

You do not have anything labeled "0s" but you have that rightmost dot that is not labeled. Is that "0s"? if so, that corresponds to 600 m, not 700. (700 m is not even on your graph.)

3. Jan 31, 2012

### chinnie15

That is the graph that is given in the problem. I didn't create it. It says this in the problem, above the graph:
The figure shows the motion diagram for a horse galloping in one direction along a straight path. Not every dot is labeled, but the dots are at equally spaced instants of time.

I just assumed that the 'x' (which I assumed was 700m) was where the galloping started? Or is the first dot where the galloping starts? I'm so confused...

4. Jan 31, 2012

### chinnie15

Shoot... just figured it out. That first dot IS the starting place (on 600m), not 'x'. So, it was -10, not -20. Got it now.

Thanks!