1. The problem statement, all variables and given/known data A mass attached to a horizontal spring is pulled to the right at t=0. The mass passes x=+10 cm at t=0.3s with a velocity 85.7cm/s. What is a) frequency b)amplitude c) phase constant 2. Relevant equations Acos(ωt+phi)= x(t) -ωAsin(ωt+phi)=v(t) 3. The attempt at a solution knowing that Acos(ω0.3+phi)= 10 -ωAsin(ω0.3+phi)=85.7cm/s diving v(t) by x(t) gets -ωtan(ωt+phi)=85.7/10=8.57s but and for phi since at t=0 x I assume is A but I am not sure so 1=cos(0+phi) so phi would be zero and amplitude is hard to find but it is the original stretched amount I think.