Here's the Question : A 5.00-kg mass is on the end of a massless rigid rod of length l=70.0cm which pivots freely about the other end. The mass is moving in a verticle circle. When the rod makes an angle of theta=55.0° with the horizontal, the speed of the mass is 1.60 m/s. a) calculate the magnitude of the force exerted on the mass by the rod. I already calculated this to be 21.9N and this is correct. b) (WHERE I NEED HELP) Calculate the speed of the mass at the highest point of the circle. Now I know I need to write the forces for this point... F = mv²/L - mg but this equation gives me 2 unknowns, where do I get a value to sub for F (the force exerted by the rod)...or is there some simplifying step I'm missing here... please help, thanks.