Improving Physics Knowledge for Exams

In summary, the Earth is able to maintain a static orbit with the sun due to the centripetal acceleration created by its rotation. However, this does not completely resist the sun's gravity and the Earth will eventually crash into it, though this process will take billions of years. This is also the reason why satellites eventually crash into the Earth. There is some debate over whether the Earth is spiraling towards the sun or away from it, with some theories suggesting that the Earth may have come from farther out in the solar system.
  • #1
tntcoder
11
0
Hi,

New to this forum and my physics isn't great, and i need to improve a hell of a lot for this years exams :tongue2:.

Firstly,

Could someone explain to me how the Earth sits in a static orbit with the sun, in that they don't move closer to each other.

As i thought until tonight, that two objects with mass will attract each other, something with the universal gravitational constant. So therefore if the Earth is in a eliptical orbit with the sun, with centripetal motion why doesn't the suns gravity pull and the fact that all particles attract other particles pull the Earth closer to the sun?



I hope this is in the right forum and thanks for any help

Cheers
Jack
 
Last edited:
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  • #2
the centripital acceleration that the Earth has while it rotates the sun is a force that keeps the two from colliding into eachoter. And by the way, the Earth is slowly moving towards the sun, and one day, it wwill crash into it. The motion is soo small that it will take billions of years for this to happen.
 
  • #3
Thank you, so is this the same reason why satellites crash into Earth eventually? they resist Earth's gravity by the centripetal acceleration but not completely and eventually it gets pulled out of orbit and will collide with earth?
 
  • #4
Satellites are slowed down by the residual atmosphere at their height. If they were in true vacuum they wouldn't crash, because conservation of angular momentum would keep them flying unless they could transfer some of it to some other matter.
 
  • #5
Nenad said:
...And by the way, the Earth is slowly moving towards the sun, and one day, it wwill crash into it. The motion is soo small that it will take billions of years for this to happen.

Wow... I've never heard that. I've always heard that the Earth will crash into the Sun because the Sun will swell up into a red giant and engulf the Earth. If the Earth is spiraling towards the Sun, what is robbing it of its orbital energy?
I would have guess the opposite. Since the Sun is constantly converting mass to energy and radiating away that energy, and blowing out a solar wind, and storms of charged particles, it would make sense that the Sun is slowly losing mass. That should cause the Earth to spiral out. The tide that the Earth pulls on the Sun should also cause it to spiral out just like our moon spirals out from Earth. But all those things combined shouldn't make much of a difference anyway.


If the Earth will spiral into the Sun, covering a distance of 1 AU over a few billion years, doesn't that imply that Earth spent the last several billion years spiraling into its current position? But since an Earth even slightly farther from the Sun would be a cold icy world in a permanent ice age, doesn't that suggest that the Earth didn't come from farther out in the solar system.

Interesting theory... You've got me curious. :smile:
 

1. How can I improve my understanding of physics for exams?

Improving your physics knowledge for exams requires consistent practice and review. Make sure to attend all your classes, take thorough notes, and participate in class discussions. Additionally, practice solving problems regularly and seek help from your teachers or peers when needed. Reviewing past exams and studying with flashcards can also be helpful.

2. Is it important to understand the underlying concepts in physics for exams?

Yes, it is crucial to have a strong grasp of the underlying concepts in physics for exams. Understanding the principles and theories behind the equations and formulas will help you better apply them to various problems and scenarios.

3. How can I effectively study for physics exams?

Effective studying for physics exams involves breaking down the material into smaller chunks and studying them one at a time. Make sure to review your notes, textbook, and other resources, and practice solving problems. It can also be helpful to study with a group or create study guides and flashcards.

4. What are some common mistakes students make when studying for physics exams?

One common mistake students make when studying for physics exams is focusing too much on memorizing formulas and equations instead of understanding the concepts behind them. Another mistake is not practicing enough problems and not seeking help when they encounter difficulties.

5. How can I stay calm and focused during physics exams?

To stay calm and focused during physics exams, make sure to get a good night's sleep and eat a healthy breakfast. During the exam, read each question carefully and take your time to answer. If you get stuck on a problem, move on to the next one and come back to it later. Remember to breathe and trust in your preparation.

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