Gravity, Satellites and Elliptical Orbit Flashcards
Just to recap, what is gravity exactly? 0-0
Gravity is a fundamental force of nature that pulls (attracts) two objects toward each other.
So, what is a gravitational field?
It’s a region in space surrounding a mass where other masses experience a force of attraction (gravity).
Can you draw a gravitational field with a smaller mass (test mass) and a larger mass, and indicate the direction of gravitational force?
SLAYYYY
What’s the concept of gravitational field?
An object with mass will experience a gravitational force if it’s within a gravitational field of another mass
Finish the sentence! Let’s say small planet SY is nearby larger planet J
The larger mass planet J will have gravitational field….
stronger than than SY, which is why S Y gets pulled towards J due to gravity
What’s the formula of gravitational field strength?
𝑔⃗=𝐺𝑚/𝑟^2
m is larger mass right??
Can yall prove that Earth’s gravitational field strength is 9.80m/s^2?
YALL SHOULD 0-0
What’s Newton’s Law of Universal Gravitation about?
Every body in the universe attracts every other body with a *force directly proportional to the product of the 2 masses *and is *inversely proportional to r^2 *(square of distance between them from the centre)
About Newton’s Law of Universal Gravitation…
WHAT DA FORMULA?
F = G ((m1m2)/r^2))
About Newton’s Law of Universal Gravitation formula…
What does G represent?
That’s the Universal Gravitational Constant of 6.674 x 10^-11
What are satellites?
Any body that orbits a more massive object due to gravitational attraction between the two
What’s a natural satellite?
Satellites that are natural like the moon orbiting the earth or the earth orbiting the sun
What’s an artifical satellite?
A man-made satellite for GPS, internet, comms, military etc
What’s the centripetal force for satellites that allow them to always be in circular orbit?
Gravity!!
If satellites are at lower attitude, what should they do to keep orbit?
Increase their speed!
What happens if satellites can’t be in circular orbit no more, what do they turn to?
They do an elliptical orbit instead!
Why if satellites’ speed are too high, they go in elliptical orbit?
Because if the speed to too much, then they need more centripetal force. But centripetal force is gravity which you can’t change.
What is the formula to help determine the speed of the satellite & how do yall derive that?
V = square root of (GM/r)
Can a satellite orbit earth NOT in the centre?
NO! because centripetal force is directed towards the centre. If no centre -> IMPOSSIBLE girliesss
What is an equatorial orbit?
An orbit that’s geostationary = to remain above the same point on Earth’s surfaces
It orbits side to side on the the Earth’s surface
What are equatorial orbits good for?
Good for monitoring things, communicating
What are equatorial orbits NOT good for
Taking detailed satellite images because it’s far away from surface
If are any issues -> $$$$$ to go up there and fix it
What is a polar orbit?
Low earth orbits (<1000m) that have low periods of 1.5-2hrs cuz they fast
Orbits around the polar caps (up and down if yk what i mean?)
What are polar orbits good for?
If combine it with many polar orbits, they can take very detailed images which is good for weather maps!
What is Kepler’s 1st Law?
All planets move in elliptical orbits with the Sun at one focus, which meant the sum of the distances from any point to the two foci is constant.
Can you draw a diagram that explains Kepler’s 1st Law?
YALL SHOULD 0-0
What’s Kepler’s 2nd Law?
“The radius vector drawn from the Sun to a planet sweeps equal areas in equal time intervals” which means the areas are always equal in size no matter where.
Can yall draw a diagram that explains Kepler’s 2nd Law?
YALL SHOULD
In regards to Kepler’s 2nd Law
Why is it when something is near the Sun, the acceleration increases?
1) When it’s near the Sun, there’s more gravity force.
2) When it’s near the Sun, distance (r) between them decreases, which increases gravity force.
F = ma, when F increase, a increase
F= (Gm1m2)/r^2 , r decrease, F incre
What’s Kepler’s 3rd Law?
A formula that T^2 = (4piesquaredrcubed)/GM
In regard to Kepler’s 3rd Law
Can you use that formula for anything? 0-0
NO only for circular orbits
