The beam has a mass m2 = 126 kg and length L = 5 m.

A gymnast with mass m1 = 49 kg is on a balance beam that sits on (but is not attached to) two supports. The beam has a mass m2 = 126 kg and length L = 5 m. Each support is 1/3 of the way from each end. Initially the gymnast stands at the left end of the beam. What is the force the left support exerts on the beam?