Actually, that does not happen until the protostar becomes a star when nuclear ignition starts and is maintained. It takes awhile for new star to go through its T-Tauri stage and settle down on the main sequence.
<span>A STAR does not reach hydrostatic equilibrium until it on the main sequence. Otherwise, it would remain a brown dwarf with not enough mass to to maintain nuclear fusion for more than 3,000 to 10,00 years. </span>
Hmm, friction maybe? I guess it depends on how fast she stopped?
No because you are supposed to do this
T for time and V for velocity or acceleration so what you do is take the two numbers
D= 3/12 it goes 12 meters every 3 seconds so you devide 12/3
So for every second the ball roles 4 meters!
Hope this helps! :)