Question

determine 3 different heights from which to perform the following experiment.

1. Lightweight trash can liner – cut 3 squares: (10”x10”), (20”x20”), (30”x30”)

2.Make a parachute out of each square by tying a piece of string to each corner, then attach the string to the sandwich bag containing a golf ball.

3.Make a prediction of which one has the best survival rate.

4.Drop the parachutes from 3 various heights, record time for each trial.

5.Compare the fall of the small parachute to the large one.

Answer 1

From basic understanding, we know that more the surface area of the parachute, more will be the air resistance. As this is an experiment based question and you are supposed to perform it.

so I have actually made two parachutes of 10 inch * 10 inch and 20 inch * 20 inch. I dropped these from a 3 storey building in my neighbourhood. Here is what I have observed

The parachute with the larger square ( 20 inch * 20 inch) has the best survival rate. It has the highest air resistance and falls more slowly under gravity.

We can find the acceleration of the parachute but that will become more complex. Still, for your understanding,

ma = mg - air resistance

a = mg - air resistance / m

Note - this air resistance term is not as simple as it looks and has so many variable factors.

Anyway, If we were to compare drop of small parachute to a larger one, Then I would say larger one falls more slowly than a smaller ones. It takes around 23 seconds (my stopwatch showed me this) from a three storey building for large parachute and around 15 seconds for smaller one . However, if we do this experiment in vacuum then both will fall in the same time.