Which stage of a stars life cycle represents a time of converting hydrogen to helium in the core. a. red giant b. main sequence c. white dwarf

the answer is d

lies a supermassive black hole called sagittarius a*, or sgr a* for short.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.