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Anthony Lu

- 7

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Hypothesis:The mass of the pendulum bob does not affect the oscillation time of a simple pendulum. This is because the force acting on the pendulum bob causing its movement is the gravitational force of earth, which stays the same at 10m/s^2 (or 9.8m/s^2). Hence, the acceleration of the pendulum bob will stay at 10m/s^2 no matter the mass. This is because according to Newton’s 2nd law, F=ma. When the mass of the object is changed, for example doubled, the net force of the object doubles. Because a=F/m, changing the mass will not affect acceleration as the doubled net force and doubled mass can cancel out (F2/m2).Conclusion:According to my results table and the graph, my hypothesis was correct. No matter the mass of the pendulum bob, the oscillation time does not change. This was proven through the graph, where a straight line of best fit was produced to show little to no change in time needed for a simple pendulum to complete one oscillation.The mass does not affect the oscillation time of the pendulum bob because the bob is being accelerated towards the ground at a constant rate of 10m/s^2. Just as objects with different masses but similar shapes fall at a same rate, the pendulum is pulled downward at the same rate no matter the mass of the bob, hence the bob will take an equal amount of time to complete one oscillation, assuming there is no air resistance.This can be further proven by Newton’s second law, as explained in the hypothesis. When the mass of the object is doubled, the net force of the object doubles because Fnet = ma. When a= F/m, the doubled net force and doubled mass cancels out, and the acceleration ends up the same. This proves why the gravitational force/acceleration of 10m/s^2 never changes and hence, it proves why the time it takes for a simple pendulum to complete one oscillation stays the same, even when the mass of the pendulum bob is changed.