(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I took a test today and I am pretty sure I got everything right except for this one problem that was on there which I am unsure of. If I remember correctly, it went like this:

It said there was a particle of mass 2 kg moving with a speed of 5 m/s to the right. Then there was a graph that more or less looked like this one I just made:

The question asked what the final velocity was after the impulse.

2. Relevant equations

I believe this is correct and relevant.

[tex]\int F dt = J = ΔP = mv_{f} - mv_{i}[/tex]

3. The attempt at a solution

I wagered that since the impulse was equal to the area under the curve on a Force v. Time graph, that the problem could be done in this way:

[tex]J = \frac{1}{2}(base)(height)[/tex]

[tex]J = \frac{1}{2}(0.10)(10)[/tex]

[tex]J = 0.5[/tex]

[tex]J = mv_{f} - mv_{i}[/tex]

[tex]0.5 = (2)v_{f} - (2)(5)[/tex]

[tex]10.5 = (2)v_{f}[/tex]

[tex]5.25 = v_{f}[/tex]

So I said the velocity afterwards was 5.25 m/s (and part b asked the direction, which I claimed was to the right).

It's unlike any practice/hw/quiz problems we have had before and there was some equation she wrote on the board:

[tex]F_{avg}Δt = mv_{f} - mv_{i}[/tex]

Which I believe is basically what I did, I just didn't use that equation.

Did I mess up?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Impulse Momentum (et al.) test

**Physics Forums | Science Articles, Homework Help, Discussion**