00:02
A star with the name i won't attempt to pronounce is 57 light years away from us, and it has a mass of 0 .85 times that of our sun.
00:11
There's a planet that is 0 .11 times the distance that we are away from the sun, and we want to then know in part a what is the orbital velocity of this planet around that star.
00:24
So, as we've been using a lot in this section, we know that for any object in circular orbits, its orbital velocity is just the square root of g times the mass, usually we'd say of the planet, i guess we'll say of the star here, so the mass of the object being orbited, divided by the orbital distance r.
00:46
So they've given us these in terms of values that we know, so we'll just substitute those in.
00:51
So g, and then the mass of this planet is 0 .85 times the mass of the sun, and the distance is 0 .11 times the distance between the sun to the earth.
01:09
So we look up those values in the appendix, and we should get that the velocity is 82 ,700 meters per second...