- #1

mattmate

Please help as soon as possible,

Thanx

matt

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- Thread starter mattmate
- Start date

- #1

mattmate

Please help as soon as possible,

Thanx

matt

- #2

mattmate

The question i need to answer is:

"Gather infomation using a wide variety of sources and carry out a simple first hand investigation to determine a value for acceleration due to gravity. Present this by:

1)Including labeled diagram

2)Showing a sample of simple calculations used

3)Identifying Independant, Dependant and constant variables"

The experiment i chose to perform is to drop a small ball froma height of 2meters. I time this, and then i was hoping to be able to answer the above question via this experiment

Thanx

Matt

- #3

Integral

Staff Emeritus

Science Advisor

Gold Member

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- 56

Also we do not do your homework for you, show us where you are and what you have done.

- #4

mattmate

Sorry, im not actully asking you to do it for me!

Basically, i have dropped a small ball from a height of 2 meters, 20 times. Each Time, i recorded the result in a table that listed the distance of 2 meters, then the time i got.

I chose to perform it 20 times, to find the average due to the human error of me timing.

I also have the mass of the ball.

We have been given no formulas or anything of such.

I was hoping someone would know a simple relationship to get a value of acceleration due to gravity to get a result similar to the accepted value of 9.8m/s2

Thanxs again

- #5

HallsofIvy

Science Advisor

Homework Helper

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1) Repeat the experiment using a different distance. Now that you know the average speed for two different distances (and the associated times) you can, at least, approximate the acceleration.

2) Use the fact (if you are allowed to- you can't get this from your experiment) that the acceleration due to gravity is constant and so the average speed is exactly half the speed at the end of the drop.

Double the average speed you got, and divide by the time. That will give the acceleration.

- #6

mattmate

Thanx Mate, ill try that,

Thanx again

matt

- #7

- 841

- 1

If you

[tex]h = \frac{1}{2} gt^2[/tex]

[tex]g = 2h/t^2[/tex]

But just by using a single height, you can't prove that the acceleration is really constant. As HallsofIvy said, you can obtain more information by varying the height.

If you know how to use a spreadsheet like Excel, the best way to do this is by a power fit to the data: plot all your h vs. t values, and then do a power fit. It assumes your data is of the form

[tex]h = Ct^\gamma[/tex]

and will tell you what C and γ are (if you tell it to display the equation).

Equating with the above expression, γ=2 and C = g/2, so you can get the acceleration of gravity g from whatever it reports C to be.

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