1. The problem statement, all variables and given/known data The position of a 49 g oscillating mass is given by x(t)= (2.3cm) cos 11t , where t is in seconds. Determine the velocity at t = 0.43s Where: f= 1.75 t=0.43s vmax=0.25 m/s 2. Relevant equations I'm using v(t)= -vmax sin (2pi*f*t) 3. The attempt at a solution Using above equation and variables I get 0.0206, which is wrong (mastering physics). Can't figure this one out..