# Drop Time Experiment

Introduction and hypothesis

The drop time of a parachute is dependent on multiple factors. Apart from mass, there is the obvious height, area of the parachute and other external factors such as wind.

Mass is one of the main effectors of the drop time of a parachute, which can be proven through Newton’s second law, F=ma (Force=mass*acceleration). Rearranged, this gives a=F/m, where acceleration can also be gravity, if falling down. Another equation is a=v/t (acceleration=velocity/time) and a=(√2s)/t (acceleration=(sqrt2*distance)/time).

The research question that this investigation will explore is: How is the drop time of a parachute affected by its mass?

Photo 1: Parachute

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Since the force of gravity is greater than air resistance, the parachute accelerates. This acceleration is not affected by the mass.

Even though mass does not directly affect the drop time of a parachute, it can do so indirectly, especially with homemade parachutes. The area of a parachute does affect the drop time – the larger the area the longer will parachute fall.

In the parachute made for this investigation, which can be seen on Photo 1 on the left, the mass affects the area.

Because of this, I predict that the drop time of the parachute will be affected indirectly by the mass, creating an exponential line of best fit.

I think this will happen because even though mass does not affect acceleration of free fall, it affects the area of a weaker material used for a parachute. I predict that because of the fact that the parachute is made of plastic, as seen on the picture, the more weight that is being added onto it, the more will it close in on itself, decreasing the area, increasing air resistance and the drop time together with it. I also predict that the parachute will not reach it’s terminal speed as there are not enough components in this investigation to investigate it that

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Whereas it is mostly constant for the first four masses, the fifth seems anomalous. This is likely due to the fact that maximum speed is slowly being reached, and therefore the parachute is starting to drop at a more and more even pace.

The average time is calculated by adding up all of the samples of each trial for one measurement and dividing them with the number of trials.

Example: for 0,030 kg 2,120 + 1,580 + 1,840 + 1,750 +1,880 = 9,170 9,170 / 5 = 1,834 s

The absolute uncertainty for each extension is calculated by taking the maximum value and subtracting the minimum value from it, then dividing the result by two. In addition, the systematic error uncertainty from the raw data table is added to the result.

Example: for 0,030 kg 2,120 – 1,580 = 0,540 0,540 / 2 = 0,270 0,270 + 0,001 = 0,271 s

• Graphing data Graph 1: Average