1. The problem statement, all variables and given/known data It was an experiment we did at school. We placed a tape through a vibrator that leaves a black dot on a tape for every 1/100 s. We dropped the tape and registered many dots. We have narrowed the experiment down to 10 dots. So we chose a dot, and registered the length between the dot before it, and after it to calculate the velocity at that dot. We did this to a dot 10 dots further down to find the velocity at that dot, so we could use the difference in distance / difference in time. This is our measurements: L_A = 0.036 m L_B = 0.044 m We "know" the time it takes for the vibrator to leave 10 dots is 10*1/100= 1/10=0.1, therefore the distance between the three dots is 0.02s. We get (0.044/0.02)-(0.036/0.02) = 0.4 0.4/0.1= 4m/s^2 = g. Thats very wrong! Any suggestions?