Title: Gravity Simulation
1Gravity Simulation
2Gravity
- Gravity is the weakest of the four fundamental
forces. - Gravity is responsible for the attraction of
massive bodies. - Gravitational force is always attractive and acts
along the line joining the centres of mass. - Gravitational force is responsible for the
formation of planets, stars and galaxies. - Gravity decides the orbital paths of the planets
and moons in our solar system.
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3Newtons Law of Universal Gravitation
- The gravitational force between the two masses
m1 and m2 is described by Newtons Law of
Universal Gravitation. - G is the universal gravitation constant.
- This relationship is an example of an inverse
square law force. - Forces are equal in size but in opposite
directions.
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4Setting up the Experiment
- This learning scenario requires flash player 10.
- Go to http//get.adobe.com/flashplayer/ to
download and install this software. - Extract the gravitysim.zip.
- Run gravitysim.swf.
- To carry out the experiment you will also need a
stopwatch.
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5The Experiment
- Drop the ball from a set distance and measure the
time it takes to hit the bottom of the box. - Repeat your measurements several times and record
them on the worksheet. - Repeat for each of the nine environments which
have gravity. - Experiment with how the ball reacts in each of
the environments by throwing the ball with the
mouse and note how this differs from Earth. - Analyse the results to obtain the value of the
acceleration due to gravity for each planet.
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6Analysing the Results
- Values for the release height and the time taken
to fall can be used to calculate the acceleration
due to gravity for each of the planets. - If it assumed that there is no air resistance and
no other downward force, the acceleration due to
gravity g is equal to a. - Since the ball has no initial velocity, u 0,
the displacement, S, can be treated as the drop
height, h. - (Eq.1) can then be rearranged to allow
calculation of the acceleration due to gravity
(Eq.2).
Eq.1
S Displacement u Initial velocity a
Acceleration t Time
Where
Eq.2
h Drop height g acceleration due to
gravity t Time
Where
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7Discussion after Experiment
- In terms of gravity, which of the environments
are most like Earth and which are the most
different? - Why does gravity vary on other planets?
- Was the gravity more difficult to measure on some
planets more than others? - What are the sources of error?
- Was there more variation in your results in
certain environments?
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8Questions, Exercises and Tasks
- Use the internet to find the difference in the
diameter of Uranus and Earth? Given the large
difference in diameter, why is the gravity
relatively similar? - If a man weighs 80Kg on Earth, how much will he
weigh on the other planets in the Solar System? - Look up the other equations of motion, what other
systems could they be applied to? - Investigate some of the ways that the value of
the gravitational constant, G, can be
experimentally determined.
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