physics
posted by Anonymous .
A person is standning on the end of a diving board as shown. The diving board is held in place by two supports. The person has a mass of 60 kg. The diving board has a mass of 30 kg. The supports are 1.5m away from eachother. The diving board is 4m long, with the person on the end of the board. Find the force of each of these supports of the diving board.
I Know that the total forces and torque needs to be zero. torque = r*F, but I don't know what needs to go where in the equation

To do this problem, you need to know where the two supports are located. Is one of them at the extreme opposite end of the board from where the person is standing?
Write two equations for the force exerted by the two supports. One of them is a force balance:
F1 + F2 = (Mb + Mp)
where Mb = board mass
Mp = person's mass
g = acceleration of gravity
The other equation is a moment balance equation. Although one can calculate the moment about any point and set it equal to zero, the problem will be simpler if you apply it at one of the support points. Then the moment due to one of the support forces will be zero, and you can solve for the other one right away.