a=F/Mass Lab

I just finished grading one section. The vast majority of you said that indeed F= Ma or a=F/M. Unfortunately only a small minority bothered to support their conclusion with calculations. This is NOT GOOD ENOUGH. You must learn to go beyond doing the absolute minimum of what you are told. I asked you to support your conclusion. Some of you said the the acceleration went down as the mass went up. This is still NOT good enough. This would be true if M = Msquared times a cubed or square root of M times cube root of a, etc. You are to make calculations to demonstrate your conclusion. Why do you think I asked you to plot a vs 1/mass. Haven't we used the slope to find relationships from assemblies of data points? Isn't the slope of your plot Ma? Is is not something you can compare with the force ( hanging mass x g) to tell quickly whether or not Ma =F?

Some of you compared Ma with F for each run. This is fine, but using the slope tends to cancel out random errors that occur in individual trials in most labs.

Some of you had bad data that came from ignoring warnings about checking the photo gate heights to make sure only the top band was blocking the light in the gate. This was particularly true on the last trials, where the third bar tends to interfere with the gate light. You should know that where you measured tiny , or even negative accelerations, its because the second gate was reading some length different from what the first gate read. Similarly, an unexpectedly large acceleration should tip you off that you read a greater length in gate 1 than in gate 2. A glance at the data should tell you where you went wrong. For example a doubling of t from the previous run where you expected a 25% increase is a tip off.