Calculating satellites´ period of revolution

AI Thread Summary
To calculate the period of revolution for a satellite orbiting 4200 km above Earth's surface, the Earth's radius must be added to the altitude. The acceleration of gravity at that height differs from the standard 9.8 m/s², and centripetal acceleration must also be considered. Importantly, the mass of the satellite is not needed for this calculation, as the gravitational and centripetal accelerations will balance each other. Understanding these concepts clarifies the overall approach to solving the problem. This foundational knowledge is essential for accurately determining the satellite's orbital period.
JukuJohannes
Messages
8
Reaction score
0

Homework Statement


Earths´ satellite orbits 4200km above Earths surface. Count satellites´ trajectory circle-shaped and calculate satellites´period of revolution.

The Attempt at a Solution


I added the Earths´ radius to the 4200 km, which represents the orbiting attitude and then my mind crashed...
please some helpo:)
 
Physics news on Phys.org
Welcome to PF.

What is the acceleration of gravity at that height? (Hint: it's not 9.8)

What other acceleration is there from circular motion?
 
LowlyPion said:
Welcome to PF.

What is the acceleration of gravity at that height? (Hint: it's not 9.8)

What other acceleration is there from circular motion?

Of course the centripetal-acceleration but I thought that I should know the mass of the satellite to calculate the acceleration of gravity...

btw.. thanks for the welcome
 
JukuJohannes said:
Of course the centripetal-acceleration but I thought that I should know the mass of the satellite to calculate the acceleration of gravity...

btw.. thanks for the welcome

Since the 2 accelerations will need to offset to stay in orbit, you won't need the mass.
 
LowlyPion said:
Since the 2 accelerations will need to offset to stay in orbit, you won't need the mass.

yeah, that settles it down, I think I can see the big picture now,
Thank You!
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

Satellite Orbiting: Speed, Period, Altitude Calc.
Replies
2
Views
3K
When do I include the Earth's radius in questions involving satellites?
Replies
5
Views
2K
What is the Correct Radius and Mass of Earth for Satellite Orbit Calculations?
Replies
1
Views
2K
How much work is done when a satellite is launched into orbit?
Replies
5
Views
2K
Effects of Varying Satellite Heights on Orbit Motion
Replies
8
Views
1K
What are the factors affecting geostationary satellite orbits?
Replies
2
Views
2K
Question regarding centripetal acceleration/period
Replies
8
Views
2K
How Does the Time Period Change with Orbit Radius in Satellite Motion?
Replies
10
Views
2K
Satellite fall and friction force problem
Replies
11
Views
2K
Apparent (clearly false) contradiction - Kepler's Third Law
Replies
2
Views
1K

Hot Threads

Recent Insights

Back
Top