A star has a spectrum with lines indicating the presence of ionized helium. This star should be classified as a(n) <u>O</u> type star.
Helium is a noble has. Its formation and ionization requires high temperature which is possible only in core of stars. Stars classified based on temperatures. Type O stars have very high temperatures (more than 30,000 K). At these temperatures, Helium gets ionized. Thus, the spectrum of O-type stars indicates the presence of ionized helium more than the neutral.
Newton's second laws tells us that the vertical motion of the rock in function of the time follows while the horizontal motion follows where is the angle of the throw with respect to the ground and is the initial speed of the rock.
Let's find the horizontal range : the rock hits the ground when which happens for <span>, and it has thus traveled </span>.
Let's find the maximum height traveled : the maximum height is obtained when the rock's vertical speed is zero, i.e. when that is to say at . At this time it has a height of
The answer is option D "<span>Energy is conserved".
The answer to this question is option D because it seems to be the best fit. Its not option A or B because energy cannot be created nor destroyed it only can be transformed into another type of energy. It shouldn't be C because energy is not always increasing because potential energy is the amount a energy that is in a object THATS NOT MOVING....therefore your answer is option D.