Falling parachute experiment

Method

The apparatus used in the experiment are a plastic bag, scissors, a set of 5 paperclips, a ruler, stopwatch or wristwatch with ability to read to at least 0.1 s, notebook and pencil.

Firstly, the plastic bag was cut into a 15x15 square. Next, strings were tied through the holes which were at each corner of the square, these strings then were tied the ends and had the length of 25 cm. After that, a paperclip was added to the end. Then the parachute was dropped from a fixed height and the time it took to fall to the ground was simultaneously being recorded. The action was performed three times to get different values of time taken and to get the average figure. Subsequently, the second paperclip was added and the method was continuously repeated until the fifth paperclip was added.

Diagram 1. The arrangement of apparatus [2]

Result

* The total weight W = mg with g = 9.8 (m/s2)

W1 = 0.001 x 9.8 =0.0098 (N)

W2 = 0.002 x 9.8 =0.0196 (N)

W3 = 0.003 x 9.8 =0.0294 (N)

W4 = 0.004 x 9.8 =0.0392 (N)

W5 = 0.005 x 9.8 =0.0049 (N)

           

The weight changed with respect to the dropping time (Graph 1). The x-axis indicates the weight (N), whereas the y-axis presents the average time (s). As it is shown, when the weight is 0.0098 N then the average time taken to drop is 3.8s.  Similarly, if the weight is 0.049N then the time is 1.5s.

Discussion

The results show that the weight is inversely proportional to the time taken to drop, corresponding with the previous study. The experiment was done well. The parachute firstly was dropped from both heights which were 1 meter and 2 meters. The height of 2 meter was chosen since the figures of time taken to fall were bigger so the changes were more significant and the action of measuring with the countdown clock was more accurate.  The parachute was hold and dropped by the first group member and the clock was timed by the other member. During the experiment, the parachute sometimes surprisingly flew on the incorrect direction and got on the table. The other possibilities of errors might be the slow reaction of the clock holder, the non-zero error of the ruler due to the ledge at the bottom of the wall.

There are several ways to reduce the errors. First is to do the experiment in a closed room in order to have no wind inside. Secondly, choose a wall that has no shelf at the bottom. Finally, use a light-gate instead of countdown clock.

References

[1]  

http://www.physicsclassroom.com/class/newtlaws/u2l3e.cfm

[2]  http://vle.london.uea.ac.uk/course/view.php?id=156&week=0#section-5