Answer:
A. 40 cm from the fulcrum
Explanation:
In order to have a balanced board, the masses should be placed such that their moments are equal in magnitude but opposite in direction. Therefore,
F₁ d₁ = F₂ d₂
where,
F₁ = Weight of Mass 1 = m₁g = (0.2 kg)(9.8 m/s²) = 1.96 N
d₁ = Distance of Mass 1 from Fulcrum = ?
F₂ = Weight of Mass 2 = m₂g = (0.4 kg)(9.8 m/s²) = 3.92 N
d₂ = Distance of Mass 2 from Fulcrum = 20 cm
Therefore,
(1.96 N) d₁ = (3.92 N)(20 cm)
d₁ = 78.4 N.cm/1.96 N
d₁ = 40 cm
Hence, the correct answer is:
A. 40 cm from the fulcrum
