00:01
So the question is, why would a planet that's in perfect circular motion have a constant speed? so the key thing to realize here is that this relates to kepler's second law.
00:16
So kepler's second law says that the area carved out by a planet or any object in motion with respect to time is always constant.
00:28
So some constant value.
00:30
So this applies to a circular orbit because say you have a time interval of three seconds.
00:39
So every three seconds, it's going to carve out an equal area of the circle.
00:45
I know this isn't centered at the, or centered at the center, but it's going to carve out equal areas of the circle.
00:54
So these would all be equal to.
00:58
So to accomplish this, usually in an elliptical orbit, that would mean that a satellite or an object with two focuses, would, one centered at the sun, of course, would have to travel faster around the foci and would travel a little bit slower when it's not next to the foci.
01:28
So why is this true? in a circular orbit, so first intuitively think about it...