1. The problem statement, all variables and given/known data A bullet of mass m is fired with a velocity of 50m/s at an angle x. At the top of its trajectory it hits a bob of mass 3m hanging by a string 3.3 m long and gets imbedded in it. The string rotates by an angle of 120 degrees. Find x and the coordinates of the bob wrt the projectile. 3. The attempt at a solution The bullet hits the bob with velocite 50 cosx. The kinetic energy of the bullet gets converted into the gravitational potential energy of the bob and the bullet. [tex]0.5m(50cosx)^2= 4mg*3.3*(1+sin30)[/tex] cosx=0.4 The answer, however, is 30 degrees. I used cosx=0.4 to solve the second part, but needless to say, that answer didnt match either. What did I do wrong? Or is the given answer incorrect?