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Fez

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Everything posted by Fez

  1. Fez
    Is that because the earth curves away or something like that? That's really hard for me to wrap my brain around
  2. Fez
    What do you mean it will take longer for gravity to slow the craft down?
  3. Fez
    Also, why does the altitude decrease by decreasing velocity?
  4. Fez
    so gravity pulls it down, but its momentum wants to push it out in a straight-line, so there's a balance between the inward pull and outward push?
  5. Fez
    Thank you
  6. Fez
    So then inertia/momentum keeps it from crashing into the surface?
  7. Fez
    I had heard that momentum is mass times velocity, and inertia is just a property of mass that keeps it going in the same direction at the same speed. But so then is it both that keep things in orbit?
  8. Fez
    So I asked a similar question a few days back, but now I have a new one. I know gravity is pulling spacecraft back to the thing it's orbiting, but what's keeping it from actually crashing into the surface? So far i have narrowed it down to 2 possible reasons: Inertia or Momentum. I know inertia is just a property of matter that makes it want to go in a straight line with the same speed. And momentum (I think) wants the object to keep going as well, because it's harder to stop something with more momentum. Inertia would work to keep the spacecraft from falling because they want to go out and away in a straight line, but gravity pulls it in, so there's a tug-of-war. At the same time, I would think momentum does the same thing, it wants to go out and away. So which is it, inertia or momentum? Or both?
  9. Fez
    Thank you for your help, I always wondered thought momentum is what kept it up, just wasn't sure
  10. Fez
    So then the force of momentum is the force that keeps it from falling back? That's what i get from the image. Hope I'm not being dense
  11. Fez
    But then what exactly is the force that cancels out gravity if it's not momentum?, that part i dont understand. What keeps it from falling back? This website says momentum is the reason it keeps from falling back, because the ship wants to travel out and away in a straight line. At least to me, that makes sense, but it might not be the actual reason i guess. http://www.schoolsobservatory.org.uk/astro/esm/orbit
  12. Fez
    So I know that the reason an orbit works is that while gravity is pulling on the spacecraft downwards, the ship's momentum pushes it out from the planet, so there's a constant tug-of-war. I also know that the equation for momentum is mass * velocity. Now, if you increase a ship's velocity, the momentum increases, and you can increase in altitude. But here's the problem: the vis-viva equation (V=√GM(2/r-1/a)) for orbital velocity doesn't take into account the spacecraft's mass. Say there's two spacecraft in circular orbit around Kerbin at 100 Km above the surface. One is 90 tons, and the other is 200 tons. Wouldn't the 200 ton spacecraft orbit at a lower velocity than the 90 ton one, because then their momentums are equal? Thank you in advance.
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