# Weight and Drag Investigation

### By: Kaven Wijeyekoon 9F

This is my investigation on weight and drag, my research question is:

## Explanation Of Science

I think the more weights we add to the parachute, the faster it will drop. This is because there will be more weight and gravity than air resistance, causing an unbalanced force and, therefore make the parachute drop faster.

## Input/ Independant Variable

We will add more weight to the parachute. We will use 5 different weights, 10g, 20g, 30g, 40g and 50g, this is to collect a range of results.

## Outcome/ Dependant Variables

We will measure the time the parachute takes to fall and using the distance, we will calculate the speed.

## Control Variables

Distance- We will drop the parachute from 7.85m every time.

Surface Area- We will keep the surface area of the parachute the same every time by using the same parachute, the surface area of the parachute will be 2500cm2, which is 50cm by 50cm. We will also use 55cm string to attach the parachute and weights, having the same length chords will help keep the parachute stable in flight.

## Apparatus

• Assembled parachute (2500cm2)
• Digital Stop Watch
• Measuring Tape (To measure height of the fall)
• You may also need paperclips and tape to help you with your parachute

## Method

1. Set up your parachute with a 10g weight
2. Drop your parachute from 7.85 m
3. Repeat test 3 times
4. Add a 10g weight to your parachute
5. Drop your parachute from the same position, 7.85m
6. Repeat test 3 times
7. Repeat steps 4-6 3 more times

## Reliability

We will get a range of results by using 5 different weights and repeat each test 3 times. This will help me find any anomalies in my results, which will give me more reliable results

## Raw Results/ Data Collection

Here is a table of my results:

## Control Variables

We dropped the parachute from the same height each time, the height was 7.85m

We used the same parachute meaning it had the same surface area which was 2500cm2

As well as the surface area, the 4 chords attaching our parachute were each 55cm long, this would have kept the parachute balanced.

## Observations

I observed that every time we added more weight to the parachute, the parachute dropped faster; this is because is was an unbalanced force. I also noticed that the more weight we added to the parachute, the less it would sway in the wind. This is because there was more weight than the wind blowing the parachute.

## Changed

The only thing we had to change from our design was that we added tape to the weights as they kept falling off once we dropped the parachute.

## Conclusion

In conclusion, my results show that the heavier parachute was, the faster it fell. The speed increased by around 30 m/s every time we added 10g to the parachute. Through the experiment, I also learnt about how the wind speed affects the fall of the parachute, and I observed that the heavier the parachute was, the less it was affected and moved by the wind.

## Explanation

Using the line of best fit you can see the correlation between the weight of a parachute and the speed it takes to fall, you can also see how the results are almost going up at a constant speed. You can see that the more weight we added, the faster the parachute fell. This is because there was more weight than the air resistance, causing an unbalanced force and consequently, the parachute to drop faster each time we added more weight.

## Evaluation

Problems:

1. We collected our results throughout 2 lessons, therefore, the circumstances were different like the rain and the windspeed.
2. After being in the rain for a while, the parachute got wet and this would have affected the results as it would have been heavier.
3. We timed the tests ourselves, meaning that the timings could have been inaccurate

Improvements:

1. We should have done the tests during 1 lesson, to make sure the variables were the same.
2. We could have wiped the parachute, but the water on the parachute would not make a significant change to the result, therefore it was unnecessary.
3. We could have used an electronic, more accurate timer which started at release and stopped as soon as the parachute touched the ground, although we do not have this equipment and it would have taken a while to set up, so it was probably better to just time the tests with a stop watch.