1. The problem statement, all variables and given/known data A mass M of 6.40E-1 kg slides inside a hoop of radius R=1.60 m with negligible friction. When M is at the top, it has a speed of 5.25 m/s. Calculate the size of the force with which the M pushes on the hoop when M is at an angle of 37.0°. [URL]http://loncapa.gwu.edu/res/msu/physicslib/msuphysicslib/13_EnergyConservation/graphics/prob25_1015hoop2.gif[/URL] 2. Relevant equations Finding the F 3. The attempt at a solution i tried 2 times and both are wrong first i tried a=v^2/r a=(5.25)^2/1.6 a=17.227 F=ma F=(.640)(17.227) F=11.025N and thats wrong... second try i draw force diagram and got tan(37)=opposite/adjacent tan(37)mg=opposite 4.726N=the horizontal force of the gravity? and its wrong.