Answer:
2400 N
Explanation:
When the boom is balanced, N = 0.
Sum of the torques about the pivot:
∑τ = Iα
-W (0.5) + F (3.0) = 0
0.5 W = 3.0 F
W = 6.0 F
Given F = 400 N:
W = 2400 N