Lab 4_Gravityandorbits(1)
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Dec 6, 2023
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Uploaded by DeanLightningFlamingo37
Lab 4: Gravitational Force and Orbits
Introduction:
Gravity attracts all objects towards each other. Gravity has been around since the very beginning of the
universe, and it works the same way everywhere in the universe, on all kinds of different objects, of all different
sizes (larger than atoms - those are held together by atomic forces instead). The bigger an object is, and the
closer you are to it, the stronger its gravitational pull is.
When one object circles another object, it is said to “revolve” around it. The Earth revolves around the Sun. The
moon revolves around Earth. You revolve around the center of a Ferris wheel. On the other hand, when an
object turns itself around (spinning) it is said to “rotate” on its axis. The Earth spinning on its axis is considered
to be “rotating.” The Earth both rotates and revolves around the Sun at the same time
Objectives:
The scientific objectives of this experiment are to
•
Determine the relationship between gravitational force, mass and distance.
•
Determine the relationship between orbital speed and orbital radius for circular orbits.
•
Calculate how changing various parameters in the Earth-Sun system affects the orbit of the Earth
Procedure:
We will be using the online Phet Simulation “Gravity and Orbits”
1.
Go to
https://phet.colorado.edu/en/simulations/gravity
-
and
-
orbits
2.
Click play arrow and choose to scale.
3.
Make sure to click Gravity Force, Velocity and Path and make sure Gravity is checked On.
4.
Run several simulations, changing parameters as you go. And answer the questions below.
Part 1: Gravitational Force
1.
What direction is the gravitational force of the orbiting object?
The satellite is orbiting around Earth moves in a circular motion towards the center, The gravitational
force is pulling the object towards it.
2.
What direction is the velocity vector of the orbiting object.
Velocity is moving counter clockwise.
3.
If you turn off gravity, what happens? Why does this happen?
If you turn off the gravity it causes Earth to float up into space because without gravity being able to
hold together the Earth it would burst.
4.
If you increase the mass of the Sun, provide an explanation of what happens to the Earth?
When you increase the mass the gravity increases.
if the mass of the sun increases so will the tempature
on Earth, it will cause shock to a lot of Earth causing any ice caps to melt and become hotter. This would
also cause other planets to be pulled closer towards the sun,
5.
If you decrease the mass of the Sun, provide an explanation of what happens to the Earth?
If you were to decrease the mass of the sun it would decrease the gravity and make the planets get off of
their orbit and the Earth would most likely die off because of the lack of the sun. We wouldn’t be able to
live without the sun.
6.
If you move the Earth closer to the Sun what happens to the gravitational force?
If you were to move the Earth closer to the sun the stronger the Sun's gravitational pull on it, and the faster the
planet moves.
7.
If you move the Earth further from the Sun, what happens to the gravitational force.
If you were to move the Earth further from the sun the weaker the Sun's gravitational pull, and the
slower it moves in its orbit.
8.
Using Newton’s Universal Gravitational law, calculate the gravitational force between the Sun and the
Earth when they are two squares apart. (You want to turn the grid on, use the provided measuring tape,
and look up the masses of the Sun and Earth.)
(6.674 x 10^-11 N(m/kg)^2) * [(1.989 x 10^30 kg) * (5.972 x 10^24 kg)] / (1.496 x 10^11 m)^2=
3.54223686 × 1022
Part 2: Orbits
For this part of the lab you may switch between the Model instead of To Scale. Only To Scale model
has the measuring take.
1.
Observe the orbit of the Earth around the Sun. Is this orbit circular? To really see if the orbit is circular
measure the distance between the Sun and Earth at two different points. Is this distance the same?
No the orbit of the Earth around the sun is not perfectly circular. It is stretched out more like and oval. The
sun and the earths are not the same at two different points in orbiting. Which helps prove the point that the
orbit is not a perfect circle.
2.
Observe the orbit of the Moon around the Earth. Is this orbit circular? To really see if the orbit is circular
measure the distance between the Moon and Earth at two different points. Is this distance the same?
No the orbit of the moon around the earth is not perfectly circular. This would mean that the distance
between the Earth and the moon varies when the moon moves along its orbit.
3.
Repeat the above for Earth and a satellite.
It would also be the same thing between the two it would not be perfectly circular because of the
gravitational pull of the earth and the velocity of the satellite.
4.
Calculate the orbital speed of the Earth. You will need the time it takes for the Earth to make one
complete cycle around the Sun and the distance between the Sun and the Earth.
Time for one revolution in days:
Time for one revolution in seconds:
Distance is the circumference of a circle is
2𝜋?
:
r is
the distance between the Sun and the Earth
using the
equation
𝑣=
𝑑𝑖𝑠𝑡𝑎𝑛𝑐?
calculate the orbital speed:
𝑡𝑖𝑚?
v = 2π(1.496 x 10^11 m) / 31,557,600 s =29,785 m/s
5.
More the Earth further away and state the orbital time for new distance. Does the time changes?
Yes, the time would change.
6.
How long does it take for the Moon to rotate around the Earth?
It takes about 28 days.
7.
Observe and describe the orbit of the moon around the Sun.
The moon does not orbit the sun it orbits around the Earth. The moon does follow the earth around the
sun so in follows its path.
8.
You can drag the green speed vector to increase or decrease it. What happens if the speed is small? What
happens if the speed is large? When you decrease the speed it makes it move slower and the direction of
motion remains the same but the object covers less distance in the same amount of time. If you were to
increase it means that it would move faster and the same thing applies it remains in the same direction of
motion but the object covers more distance in the same amount of time.
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