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,
Fâ dâ = Fâ dâ
where,
Fâ = Weight of Mass 1 = mâg = (0.2 kg)(9.8 m/s²) = 1.96 N
dâ = Distance of Mass 1 from Fulcrum = ?
Fâ = Weight of Mass 2 = mâg = (0.4 kg)(9.8 m/s²) = 3.92 N
dâ = Distance of Mass 2 from Fulcrum = 20 cm
Therefore,
(1.96 N) dâ = (3.92 N)(20 cm)
dâ = 78.4 N.cm/1.96 N
dâ = 40 cm
Hence, the correct answer is:
A. 40 cm from the fulcrum