Final answer:
B.The plank can be balanced by placing the 10 kg weight twice as far from the fulcrum as the 20 kg weight, using the principle of torques in static equilibrium.
Step-by-step explanation:
To determine if a plank can be balanced with 20 kg placed on one side and 10 kg on the other, we use the principle of torques in static equilibrium. The condition for static equilibrium is that the net force and the net torque on the system must both be zero. To achieve balance, the torque produced by the 20 kg weight must be equal in magnitude but opposite in direction to the torque produced by the 10 kg weight.
Using the formula for torque, τ = r × F (where τ is torque, r is the distance from the fulcrum, and F is the force), we find that the 10 kg must be placed at twice the distance from the fulcrum compared to the 20 kg to balance the plank. This is because the torque is the product of the force and the distance from the pivot point, and the distance compensates for the reduced force.
In this experiment, the plank can be balanced with only 10 kg on the right side if the 10 kg is placed twice as far from the fulcrum as the 20 kg. Hence, the correct answer is "Yes, if the 10 kg are placed twice as far from the fulcrum as the 20 kg.".