We put cylinder on a 表 and push. It starts roll but after some time it stops. Why, what kind of forces make it move?

OH! I know the black hole one!
I ceebs to write about cylinder atm.

Right, so when a large 星, 星级 (blue giant) burns up all of its fuel, it expands and becomes a red supergiant. This then runs out of fuel, collapses and blows off its outer layers in a huge explosion - a supernova. It collapses to a very dense neutron star, but if it still has a big mass, it collapses under its own gravity - the gravity becomes so strong that nothing, not even light can escape it, thus we get a black hole.
The official definition of a black hole is a reigon in 太空 where the gravity is so strong that nothing can escape it.
I'll get back to 你 on the cylinder stuff.

jaspers the answer! :}


he's such a cutie

CHANGING MY ANSWER TO:
Newton't First Law of Motion...
An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon 由 an unbalanced force.

i dont really know the answer, but i'm bored so i'll just make something up(;

well the cylinder stops because the sides of the 表 are slanting inward like a "V" and it gets stuck in the middle. the force that made the cylinder 移动 in the first place was gravity: obviously, if 你 place an object at the 最佳, 返回页首 of a Vshaped 表 its going to fall (or roll in this case) right to the middle of it.

A black hole is bottomless hole of nothingness where small objects could get sucked in it. really its nothing to worry about. but a supermassive black hole is definitely something to worry about! 你 can tell when they are about to form when glaciers melt in the dead of night. but supermassive black holes usually only suck up superstars, so 你 shouldnt worry TOO much about these. they are actually really interesting, they even inspired the song "Supermassive Black Hole" 由 Muse. 你 can find this song in the baseball scene in Twilight(:

Contact Force is the answer! Ha!!

the cylinder rolls because of gravity and then stops because of the force of friction.