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

A one-dimensional force acts on a particle of mass m = 6.26 kg in such a way that its position is given by:

x = 0.484t3 - 33.6t

Find W, the work done by this force during the first 1.49 s.

2. Relevant equations

F=mg

F=ma

W=F*distance

3. The attempt at a solution

To find the distance, I plugged in 1.49 into the formula they gave, and I got (-48.5). I know that to find work, the formula is W=F*s, so in order to find the force, I'm not sure which formula to use.

I think I should be using F=ma, and to find the acceleration, I can take the second derivative of the given formula. However, I forget whether that is allowed in one-dimension. If not, then do I use F=mg? If I use F=mg, then the answer for work will come out positive. If I use F=ma, then the work comes out negative.

Here are my results:

W=Fs

W=ma*s

W=6.26*18.18*(-48.5)

W=(-5519.6)J

W=Fs

W=mg*s

W=6.26*(-9.81)*(-48.5)

W=2978.4 J

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# Homework Help: Not sure which formula to use! Deals with work and position

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