y=A cos (ωt+ø)
I use t=0, y=15cm and t=0.3, y=A to get 2 equations:
However there are 3 unknowns in these 2 equations, and I just do not know how to get the 3rd equation from the given quantities. Is this question miss something? Should it tell me the value of force constant k or sth. else? Please help to solve, thanks a lot!