I am designing a lab to prove that F=ma. However i am only using a spring scale, 1 kg mass, string. I have come up with a procedure where you would attach the mass to the scale and accelerate the unit upward, recording the time it takes the unit to accelerate from 0-1m and the force shown in the scale. From these measurements i can find the acceleration and than prove that T-ma=mg. However, there is great percent of error as the acceleration by hand proves inconsistent. Is there anyway to get a constant acceleration by hand using the materials listed above?