Is My Calculation of Applied Force in a Pulley System Accurate?

[kieran89]

1. Hello. I am doing a practical assignment which involves a pully system with different masses on each side attached to a string. I have figured out acceleration via a = 2x/t^2 and then Force applied by F = (.42-.38)*0.286 which gives me 0.011N. However when I graph the final solution (I have changed the weight difference (.430 and .390) as a Force (yaxis) and Acceleration (xaxis) graph it is basically saying that at 0N applied i am getting 0.18ms-2!.

2. x=1.48m

Am i calculating the applied force correctly?

3. m1 (kg) m2 (kg) t (s) a (m s-2) aaverage (m s-2) Fapp (N)
Trial 1 0.420 0.380 3.21 0.287
Trial 2 0.420 0.380 3.25 0.280
Trial 3 0.420 0.380 3.15 0.298 0.286 0.011
Trial 4 0.420 0.380 3.17 0.295
Trial 5 0.420 0.380 3.22 0.285

 

[kuruman]

I am not sure I understand what you are plotting. You have shown 5 trials and one average value of the acceleration. Then you calculate an average acceleration and from this a "force" as the mass difference times the average acceleration. Did you collect data with other mass differences and put them on the same plot?

Your calculation for the "applied force" seems to be correct. However, you can always multiply the average acceleration and the mass difference together. The question is, how do you interpret the result?