1. The problem statement, all variables and given/known data I know this is long, but that is only because this question requires me to be thorough, conceptually I think it isn't difficult. To make it easier to read I bolded the important parts. In Physics lab, we were told to conduct an experiment to investigate the effect off mass on the skidding distance of a car. We conducted the experiment using a model cart, a dynamic track, a spring launcher(one in which the force could be altered), a motion detector and weights. The spring launcher was used to supply a constant force for each trial of the independent variable. The motion sensor was connected to logger pro and recorded the distance and velocity per 0.05 seconds. Unfortunately our experiment was flawed because we didn't have a strong enough spring to launch the cart when the wheels were taped. We were told to proceed without taping them. As we added 200g masses to the cart, we also used hooks law(f=kx) on the spring launcher to increase the force that pushes the cart. We did this because the extra weight would cause the launch velocity drop even when we needed it to stay constant. Just in case this wasn't enough, we used the motion sensor as a precautionary measure to see if we succeeded at keeping the velocity constant. We recorded the position the cart was at when it stopped. The first problem is that even though I believe we used hook's law correctly, according to the motion sensor, the cart started off going much faster as we added weights. So we ended up using the data collected by the motion sensor to find out at what position the velocities were constant. Then found the difference between this and where the car stopped. This was our skid distance. We took the average of all skid distances per each independent variable value and our results are shown below. The standard deviation of the trials was not small. mass of cart (g) Avg skid distance (cm) 566.9 17.9 766.9 24.35 966.9 22.7 1166.9 19.45 1366.9 19.9 Second problem is that there appears to be no trend in our results. We had hypothesized that as we increased the weight, the skid distance would increase proportionally because of inertia. This does not appear to be the case. 2. Relevant equations F = ma = m(vf-vi)/t = kx (vi is zero because the car starts at rest) F = m(vf/t) = kx vf = kxt/m F(friction) = N*(coefficient of friction) 3. The attempt at a solution I have no explanation for the first problem except for the possibility that time might not have been constant. In the second problem, I thought of the force of friction and how it should increase proportionally with the added weight. So effectively this should cancel out the effect of the weights on increasing the skid distance resulting in a constant skid distance. I really think this is plausible especially because of the last two points in our graph. With more data I believe we would see the trend better. What do you think, Do you spot any other flaws is the experiment.