Models of the first star-forming clouds indicate that they had a temperature of roughly 180 k and a particle density of roughly 3.50×105 particles per cubic centimeter at the time they started trapping their internal thermal energy.

part a: estimate the mass at which thermal pressure balances gravity for these values of pressure and temperature.

part b: how does that mass compare with the sun's mass?

part c:

what is the estimated lifetime of a star with that mass?

choose the answer that best fits your estimate

greater than 10 million years
less than 10 million years
about 10 billion years
about 1000 years

Momentum lab this lab uses a phet simulation. navigate to the phet momentum simulation. if you don’t see the image below when you click on the link, then you need to either enable adobe flash (click on the puzzle piece on your screen) or you need to install adobe flash (this is a free program). change the vectors to be momentum vectors only. they are yellow. make the mass of both balls the same. hit play and notice what happens to the momentum vectors before and after the collision. you might want to play the sim multiple times. click on restart or return balls to start over. to see numbers, check the show values box (inside the green box). red’s momentum vector before the collision is green’s momentum vector after the collision. question 1 options: shorter than longer than equal to question 2 (1 point) saved since green bounces off red, this must be an collision. question 2 options: explosion inelastic elastic question 3 (1 point) red transfers of its momentum to green during the collision. question 3 options: little all most none question 4 (4 points) why does red transfer all its momentum to green? back up your answer with information from the simulation. write at least 2 sentences.