Answer:
F = 50 N
Explanation:
As we know that block is floating in the water with half of the volume submerged into it
So we will have
[tex]F_b = mg[/tex]
at equilibrium position the buoyancy force on the block will be equal to the weight of the block
Now the weight machine will measure the net normal force for which we have
[tex]F_n = W + F_b[/tex]
so here we have
[tex]F_n = 40 + 10 [/tex]
[tex]F_n = 50 N[/tex]