The aim of this experiment was to investigate the relationship between the centripetal force acting on an object moving in a circle of constant radius and the frequency of revolution. To reach the aim I have done this experiment by following the procedures with twirling the stopper in a horizontal circular path at a constant velocity that pulled the paper clip up to, but did not touch the bottom of the tube. Then rotated automatically and measured the time taken for 10 revolutions of the small mass. The variable that I changed was the mass of the load. These changes would take effect on the dependent variable which was the frequency of the swing hence centripetal force. The variable that I kept constant was the length of the horizontal string and also the small soft mass (rubber stopper).
My hypothesis stated that The centripetal force of an object of mass (m) moving at a constant velocity (v) and radius (r) is given by F = = 42rmf2. where: Fc is the centripetal force in N Fg is the force of gravity in N r is the radius of the string in m ms is the mass of the rubber stopper in kg ml is the mass of the suspended load in kg g is the gravitation in m s-2 From that equation, I can deduce that if the frequency of object spinning is increased, the centripetal force will increase. Also, in this experiment, the force of gravity acting on the suspended mass should be the one providing the centripetal force. This force is given by: where in this case m is the mass of the suspended load and g is the gravity.
There were some relationships between centripetal force and the frequency of rotation. From the graph, I can analyze the relationships between the centripetal force and frequency. From the table and graph I can state that as frequency increases, centripetal force will also increase. The relationship between the frequencies squared is linear with the centripetal force (direct variation). From the theory that stated The centripetal force of an object of mass (m) moving at a constant velocity (v) and radius (r) is given by F = = 4?2rmf2.So that if the frequency bigger, the centripetal force must be bigger too and my result have shown that the theory was correct.
There were some difficulties that we had during this experiment such as it was hard to keep the speed constant when we swang the mass. Because every time our hand easily shaking (not constant), and also sometimes the swing rotation was not in horizontal line. That problems will cause our results become less accurate. Furthermore there was also some difficulties that we have when we need to swing it with the constant power and speed, sometimes our hand also touched the string that no supposed to be touched when it did the revolutions. The stopwatch delay also affected our results because when the experiment ended with 10 revolutions, my friend was late or not perfect to press the stopwatch so that there will be stopwatch delay.
There will be some improvements in this experiment that I need if I’ll do this experiment again. First of all we need to practice to swing it horizontally, and when we want to record the revolution after 10 swings, we must carefully count the revolution because sometimes our eyes can’t follow the revolution. Secondly, we also need more careful when swing because sometimes the mass can contact our head or our friends. I also need to keep the string is not moving so that the length can be measured perfectly. To get more accurate results, we can also give an alternative independent variable such as the length of the string. By getting the results from the different mass and different length of string it will make the data more accurate to prove the theory and hypothesis.