Finally, spin the apparatus up to the rotational speed at which the mass hangs at the same radial distance from the axle as the pointer. You have already measured the force the spring is exerting at this position, so you know the value of the centripetal force that is keeping the mass on its circular path. Now, you need to measure the speed of the mass. You have been provided with a stopwatch for this measurement. Talk to the instructor or your TA about your strategy.
Analysis Draw a free body diagram showing all of the forces acting on the mass.
Determine whether your measurements agree with this model within uncertainty. Evaluate uncertainties using the method you learned in Lab 3. Again, using a spreadsheet is a good approach to this analysis. Include a free body diagram and a derivation of Equation 3 . Pay careful attention to uncertainties in measurements and propagation of uncertainties to your results.