# Determine acceleration from experiment (Newton 2nd Law)

I have done a physics experiment (setup below). And was asked to determine the experimental and theoretical acceleration.

The data I've got

Ok, am I right to say

Experimental acceleration = $2(s_f - s_i) / t^2$

Theoratical acceleration = $m_2 \times 0.98 / m_1$

Then

Percentage discrepancy = $\frac{|(Experimental - Theoretical)|}{Theoretical} \times 100$%

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Hi Jiew - your question seems kind of unfocused. What concept is it specifically that is confusing you? Are you confused about why the mass of the cart affects its horizontal acceleration? Or are you confused about some step in the calculation of the theoretical acceleration? It would help a lot if you edit your question to focus on the one thing you want to ask. If you have multiple concepts to ask about, you can post more than one question about the same lab setup. –  David Z Sep 27 '12 at 4:30
Ok, I edited my post and posted another question physics.stackexchange.com/questions/38448/… –  Jiew Meng Sep 27 '12 at 6:25

If by $s_f$ and $s_i$ you mean the final and initial position, respectively --- so that $s_f-s_i$ is just $d$ in your table --- then yes, your experimental acceleration is right. As for your theoretical acceleration, it should be $\frac{9.8m_2}{m_1}$, not $0.98$ --- the acceleration due to gravity is $g=9.8$. I'm assuming you just made a typo. Your definition of percentage discrepancy is right.