First of all sorry if this is the wrong section! For a physics assignment, I am given a graph of which I am to gather data from. Graph 1: In an experiment to investigate how the celcius temperature, T, affects the volume, V, of an enclosed sample of air at a constant pressure, a students graphed results appear as shown below. Questions: (1) Is V directly proportional to T? (2) Is ΔV directly proportional to ΔT? (3) From the graph, determine an expression for V in terms of T. (4) Hence determine the value of T when V = 0. My thoughts: (1) V is not directly proportional to T as the graph does not pass through the origin (0,0). This graph represents linear dependence. (2) ΔV is directly proportional to ΔT as a straight line is produced. If you double V, T will double. If you half V, T will half...etc. (3) I'm kind of stuck for this one. I don't know how to determine as expression. I know that when V = 80, T = 0. So if I use the equation of a straight line, I get y = mx + c, 80= mx + 0 m = -80? which seems wrong to me, I'm probably approaching it in the wrong way. I don't know what else to say. Is V is not directly proportional to T, the statement I need. (4) For this I would obviously need to do question 3. Then plug in V = 0 and solve for T. I would then use extrapolation to show the value of T when V = 0. So that's what I need help with! If you could help me with question 3 I would be so greatful! Also could you please check my logic with questions 1 and 2. Thank you!