Static Equilibrium Problem

1. The problem statement, all variables and given/known data

Two supports, made of the same material and initially of equal length, are 2.0m apart. A stiff
board with a length of 4.0m and a mass of 10 kg is placed on the supports, with one support
at the left end and the other at the midpoint. A block is placed on the board a distance of
0.50m from the left end. As a result the board is horizontal. The mass of the block is:

A. zero
B. 2.3kg
C. 6.6kg
D. 10 kg
E. 20 kg

2. Relevant equations

∑F = 0 = N1 + N2 – mg – Mg
∑τ = 0 = -1/2 N1 + 1/2 N2 – 1/2 Mg

3. The attempt at a solution

Those equations above are a result of a free body diagram I drew. However, if I begin to solve the equation for m, I end up with an expression in terms of N1 (ie. 2N1 = mg). Is there enough information in the question? By the way, I’m calculating torque from the position where the mass is placed.

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