A uniform plank of weight 150N and of length 4.0m rests horizontally on two bricks. One of the bricks is at the end of the beam. The other brick is 1.0m from the other end of the plank.
a) Sketch the arrangement and calculate the support force on the plank from each brick
My answer for A was: 50N and 100N.
b) A child stands on the free end of the beam and just causes the other end to lift off its support. Sketch this arrangement and calculate the weight of the child.
I'm stuck on how to solve this question. The answer is supposed to be 150N.