1. The problem statement, all variables and given/known data Part (a) of the figure below is a partial graph of the position function x(t) for a simple harmonic oscillator with an angular frequency of 1.35 rad/s; Part (b) of the figure is a partial graph of the corresponding velocity function v(t). The vertical axis scales are set by xs = 6.5 cm and vs = 7.0 cm/s. What is the phase constant of the SHM if the position function x(t) is given by the form x = xmcos(ωt + ϕ)? 2. Relevant equations x = xmcos(ωt + ϕ) v = -ωxmsin(ωt + ϕ) 3. The attempt at a solution For the X vs. t graph the line crosses t=0 when x = 2.6. For the V vs. t graph the line crosses t=0 when v=-5.6. I thought then I could just plug all the number in and find out when they are equal 2.6 = 6.5cos(1.35*0+ϕ) -5.6 = -8.775sin(1.35*0+ϕ) I subtracted 2.6 from both sides for the first equation and added 5.6 to both sides for the second. I then set them equal. I used my calculator to attempt to solve them. Looking at them separately it looks like it should be 1.15 radians for X and .69 radians for V (Roughly). I can't figure out what I'm doing wrong. Perhaps I shouldn't be reading the graph like I am. or I am simply reading it wrong.