A rolling cart carrying books has a mass of 30 kg and is shoved so that it is given an initial velocity of 3 m/s. The cart's bearings are such that the coefficient of friction can be treated as 0.2 and friction acts to slow the cart to rest. a) What is the magnitude of the cart's acceleration as friction acts upon it?
b) How much time does it take for the cart to come to rest?
c) How far does the cart roll before it comes to rest?

The “death throes” of stars are amongst the most complex phenomena in all of astronomy, and the “corpses” of stars amongst the most energetic and exotic objects in existence. beginning at the end of the core helium fusion stage in a star’s life, describe in detail the post-main sequence development of both (a) a 1.0 solar mass star, and (b) a 25.0 solar mass star. in what significant ways do they differ? what role does each of these types of stars play in the "star-gas-star" cycle and the evolution of chemical elements in our galaxy?

Explain why you think this diagram shows what happened to the carbon in the biodome.

What happens to an isotope during radioactive decay?