• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

To investigate the relationship between the velocity of a parachute and the drag force.

Extracts from this document...


James De Souza        Science 1        B.E.Tyler

To investigate the relationship between the velocity of a parachute and the drag force.

Viscosity :- The viscosity of a fluid is a measure of its resistance to flow. Viscous forces acting on bodies moving through a fluid and in fluids moving through pipes and channels. The pressure in a fluid decreases where the speed increases.

Stokes Law :-  An equation relating the terminal settling velocity of a smooth, rigid sphere in a viscous fluid of known density and viscosity to the diameter of the sphere when subjected to a known force field. It is used in the particle-size analysis of soils by the pipette, hydrometer, or centrifuge methods. The equation is:

V = (2gr²)(d1-d2)/9µ


V = velocity of fall (cm sec-¹),

g = acceleration of gravity (cm sec-²),

r = "equivalent" radius of particle (cm),

dl = density of particle (g cm -³),

d2 = density of medium (g cm-³), and

µ = viscosity of medium (dyne sec cm-²).

A falling object has an acceleration equal to g, provided air resistance is negligible. If air resistance is significant, the force due to air resistance drags on the object. This drag force increases as the object speeds up, until the force becomes equal and opposite to its weight.

...read more.


0.20         1.03         0.97         1.10                 1.04                 2.74                         2.63

Experiment 2
Mass (N) Time 1 (s) Time 2 (s) Time 3 (s)   Average Time (s)    Average Velocity (m/s)*  Average Acceleration (m/s2)…
0.02         2.78         2.32         3.28               2.79                        1.02                         0.37
0.04         2.18         2.30         1.67               2.05                 1.39                         0.68
0.06         1.57         1.40         1.50               1.49                 1.91                         1.28
0.08         1.09         1.14         1.25               1.16                 2.46                         2.12
0.10         1.19         1.31         1.29               1.26                 2.26                         1.79
0.12         1.13         1.20         1.14               1.16                        2.46                         2.12
0.14         1.09         1.07         1.13               1.10                        2.59                         2.35
0.16         0.91         1.08         1.10               1.03                        2.77                         2.69
0.18         0.88         1.01         1.06               0.98                        2.91                         2.97
0.20         0.93         0.97         1.00               0.97                        2.94                         3.03

Averages Over Experiments 1 and 2
Mass (N)         Average Time (s)

...read more.


ii)         v2 = u2 + 2as
iii)         s = (u + v)

Unfortunately, without knowledge of the terminal velocity, or the real acceleration, this can’t be done properly. However, to give a rough idea of how it could be used, the test is detailed below:

In an attempt to acquire the most accurate results possible, albeit a futile attempt, the third formula will be used and the average velocity used in place of the terminal velocity.

1) To begin with, try the first set of results, i.e. a mass of 0.02 N:

s =
(0 + 0.93)
\ s = 0.465

Quite obviously, this distance is nowhere near the actual distance of 2.85m but, of course, it shouldn’t be because with such a small mass, air resistance is still playing a major part.

2) Next, the results for a mass of 0.12 N will be tried:

s =
(0 + 2.32)
\ s = 1.16

Again, this is nowhere near the actual distance but it is getting closer.

3) Lastly, the results for the last mass, 0.20 N, will be tried:

s =
(0 + 2.94)
\ s = 1.47

It would appear then, in conclusion, that this test was a failure. The question is, though, is this because of the fact that the final velocity is obviously false, or because this is not the way to go about finding the “terminal” terminal velocity, which of course may not exist. In all likelihood, however, looking at the results, it does exist but without the actual values for the final, or terminal, velocity, it is difficult to prove its existence.


...read more.

This student written piece of work is one of many that can be found in our GCSE Forces and Motion section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Forces and Motion essays

  1. To determine the relationship between mass and acceleration when force is kept constant.

    This accounts for the 'error' in reading at the start, but still there is an error in the overall gradient of the graph. Conclusions: Overall my results were not as I would have expected them to be, but I had provided sufficient reasons for this.

  2. The effect of the temperature on the viscosity of the syrup.

    10 11.2 8.93�10-3 0.159 10 12.1 8.26�10-3 0.136 Prediction At high temperature the viscosity of the syrup will be low. This is because the molecules gain energy at high temperature, which reduces the syrup's resistance to flow, since the friction between the layers is also reduced.

  1. Investigating the effect of mass on a parachute

    Mass (g) 0g 5g 10g 15g 20g 25g 1st Run 2nd Run 3rd Run 4th Run 5th Run 6th Run 7th Run 8th Run 9th Run 10th Run Pilot Test I am now going to construct a pilot test to test whether my method (detailed plan)

  2. The aim of this investigation is to see what the relationship between force, mass ...

    0.831 1.604 0.773 8 4.13 0.831 1.937 1.106 10 3.95 0.831 2.531 1.700 Actual results force Average acceleration Actual mass Generated mass Difference Between 2 masses 3 2.234 0.831 1.342 0.511 4 2.938 0.831 1.361 0.530 5 3.358 0.831 1.488 0.657 6 3.692 0.831 1.625 0.794 7 3.998 0.831 1.750

  1. Viscosity of Fluids

    Gravitational field: The ball bearings fall through the honey due to the attraction created by the gravitational field from the Earth. In this investigation, this can be considered constant at 9.8ms-2. 4) Distance: In order to make accurate measurements on the terminal velocity of the ball bearings the distance over which their speed is measured must be kept constant.

  2. The Area of a Parachute Compared To Its Rate of Descent

    The histogram shows that this a direct proportion in the histogram. Evaluation - Accuracy and Reliability The accuracy of my results was fairly good from my opinion. There was one anomalous result in the graph. The graph actually showed a positive result in that it was a particular shape, exponential.

  1. In this experiment I aim to find out how the force and mass affect ...

    One cannon ball was heavier than the other was. Galileo's professor was highly sceptical about Galileo's idea and so Galileo had the professor lie at the bottom of the tower with his ear to the ground! This was so that the professor could listen out for the two thuds as one cannon ball hit the ground before the other one.

  2. Practical Investigation Into Viscosity

    that of a mouse - the terminal velocity of a man (about 100 mi/hr) would be 25 times that of a mouse! Dropping a sphere of known size and mass in a liquid and measuring its terminal speed is one way to measure viscosity.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work