A plank 3m long and having a mass of 20kg is supported at its ends. Imagine that a person with a mass of 50 kg stands m from one end. What are the magnitudes of the force exerted by the supports?

Answer 1

the supports each exert 98 N to support the plank

one support exerts [490 N * m / 3]
to support the person

the other support exerts
... 490 N - [490 N * m / 3]