Satellite in orbit - forces involved

AI Thread Summary
A satellite in orbit experiences free fall, meaning the only force acting on it is gravity. This gravitational force acts perpendicular to the satellite's direction of motion, resulting in no work being done, allowing it to maintain a constant speed and height. The satellite orbits the Earth every 120 minutes, indicating a balance between gravitational pull and its tangential velocity. If another force were to act on the satellite, it would either slow down, causing it to descend, or speed up, leading it to ascend. The discussion also touches on the origin of the exam question, questioning its wording and source.
jsmith613
Messages
609
Reaction score
0

Homework Statement


A satellite orbits the Earth once every 120 minutes.
The satellite is in a state of free fall. What is meant by the term free fall? How can the height of the satellite stay constant if the satellite is in free fall? [3 marks]

Homework Equations


none

The Attempt at a Solution


So is this correct:

Free-fall: when the only force acting on an object is the gravitational force
- as the force is acting ppd to direction of motion, no work is done on the satellite
- the satellite moves in a circle at a constant speed at a constant height
 
Physics news on Phys.org
Hi jsmith!

jsmith613 said:
So is this correct:

Free-fall: when the only force acting on an object is the gravitational force
- as the force is acting ppd to direction of motion, no work is done on the satellite
- the satellite moves in a circle at a constant speed at a constant height

Yes! :smile:
 
jsmith613 said:

Homework Statement


A satellite orbits the Earth once every 120 minutes.
The satellite is in a state of free fall. What is meant by the term free fall? How can the height of the satellite stay constant if the satellite is in free fall? [3 marks]


Homework Equations


none

The Attempt at a Solution


So is this correct:

Free-fall: when the only force acting on an object is the gravitational force
- as the force is acting ppd to direction of motion, no work is done on the satellite
- the satellite moves in a circle at a constant speed at a constant height

Because the satellite is moving very fast. Another force would either slow the satellite down, so it would move closer to the earth, or speed it up, so it would move away from the earth.
 
jsmith613 said:

Homework Statement


A satellite orbits the Earth once every 120 minutes.
The satellite is in a state of free fall. What is meant by the term free fall? How can the height of the satellite stay constant if the satellite is in free fall? [3 marks]


Homework Equations


none

The Attempt at a Solution


So is this correct:

Free-fall: when the only force acting on an object is the gravitational force
- as the force is acting ppd to direction of motion, no work is done on the satellite
- the satellite moves in a circle at a constant speed at a constant height

I am an exams officer for a UK exam board. Can you let me know where this exam question came from ?.,... is it an exam question or a question from a teacher?

are you sure youhave worded the question correctly??
 
Last edited:

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Effects of Varying Satellite Heights on Orbit Motion
Replies
8
Views
1K
Does an orbiting satellite speed up as it falls towards earth
Replies
3
Views
2K
How much work is done when a satellite is launched into orbit?
Replies
5
Views
2K
Change in momentum for a satellite in circular orbit
Replies
6
Views
3K
Satellite fall and friction force problem
Replies
11
Views
2K
Satellite Motion Homework: Find 2nd Satellite Speed
Replies
2
Views
2K
Calculating Energy for Satellite Orbit at 300km | Physics Homework Help
Replies
37
Views
3K
Circular orbit change after gaining mass ejected from sun
Replies
1
Views
1K
Satellite Orbiting: Speed, Period, Altitude Calc.
Replies
2
Views
3K
Speed of satellite orbiting around the Earth
Replies
7
Views
2K

Hot Threads

Recent Insights

Back
Top