[SOLVED] Tension in two cables The problem statement, all variables and given/known data 21.0 kg loudspeaker is suspended 2.40 m below the ceiling by two 3.90 m long cables that angle outward at equal angles. The attempt at a solution So my homework comes from the MasteryingPhysics online homework. What I first start out with is my free body diagram. I have 3 arrows, one pointing down for weight of the speakers by the earth (Wse) and two arrows pointing up diagonally (Ts1 and Ts2). Since the speaker is static you have Ts1 + Ts2 + Wse = 0. That was about as far as I could go. I then looked up information in my book but couldn't find much and so I resorted to the internet. I came across this page: http://science.palomar.edu/physics/Physics230/Tutor/4-31.html I used the equation they give T = mg/2sin(theta) I set a x-y axis starting with the speaker as the origin. I find the triangle that one string forms with the y-axis and the ceiling. I find the angle that corresponds with the picture on the page I found and plug in the information I have into the equation: T = (21*9.81)/(2sin(37.98)) Putting this data into the answer box, I get the feedback: "Remember to use radians, not degrees, in arguments to trigonometric functions." I don't lose any attempts with the answer so I think I'm on the right track but I don't know what to do at this point.