# Is xf=xi +vixΔt accurate?

1. Apr 9, 2012

### anthony123456

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

Is the following formula accurate?: xf=xi +vixΔt
This question is for the hypothesis in our lab report. If we solve for the xf experimentally (in the lab), will the answer we get be the same if I do it mathematically. If so, why?

2. Relevant equations
xf=xi +vixΔt
to solve for Δt, use: yf = yi + viyΔt + 1/2a Δt^2
vix is solved in the first part of the experiment...

3. The attempt at a solution
The following formula is accurate as the x velocity is constant, thus whatever distance traveled, the distance traveled will be the same per second. What else can I say about it?

2. Apr 9, 2012

### BruceW

Yep. Maybe you are supposed to think of some reasons why the x velocity is not exactly constant in the experiment.

3. Apr 9, 2012

### anthony123456

Thank you for responding. I need to say why the answers for xf will be the same (mathematically and experimentally). The vix is always constant, according to our teacher (air resistance is negligible).

4. Apr 9, 2012

### BruceW

Then maybe you are supposed to talk about why the equation is true given that the velocity is constant. Do you know much about calculus?

5. Apr 9, 2012

### anthony123456

maybe, and I will be learning calculus next year. Why do you ask?

6. Apr 9, 2012

### anthony123456

How can I explain that the equation is true?

7. Apr 9, 2012

### BruceW

Well, you are given that the speed is constant, and how (in calculus) are speed and position related?

8. Apr 9, 2012

### anthony123456

I am not too sure... How are they related? Is it because there is no acceleration in the x-direction so speed and position are related proportionally, so to speak? This is a guess.

Last edited: Apr 9, 2012
9. Apr 9, 2012

### BruceW

pretty much, but if you haven't done calculus, then I don't think you'd be expected to give this kind of answer. Maybe you are supposed to say why there is no acceleration in the x-direction, like why the air resistance doesn't affect the outcome in this case.

10. Apr 9, 2012

### anthony123456

Ok thank you, I will do my best. Thank's for the assistance!

11. Apr 9, 2012

no problem!