Final answer:
The question pertains to the mass of a board on a balanced seesaw, which is a Physics problem. Using equilibrium and the principle of torques, the mass of the board is irrelevant to the balancing of the seesaw if the boys are positioned to create equal torques. Therefore, the mass of the board can be any value.
Step-by-step explanation:
The subject of the student's question involves finding the mass of a uniform rectangular plate, which can be done using the principles of Physics, particularly leveraging the concept of torque and equilibrium. To determine the mass of the board in the given seesaw problem (Question 33), we consider that the seesaw is in equilibrium; thus the torque produced by the weights of the boys must balance the torque due to the weight of the board. In the context of the other questions provided, they too relate to Physics and deal with various topics such as spring constant calculation, calculation of stress in a material, and center of mass.
However, since the original question specifically asks for the mass of the board in the seesaw problem, let's focus on that. We know the seesaw is balanced and therefore the torques must be equivalent. With an 80 kg boy at 3 m from the fulcrum, the torque due to his weight is 80 kg × 3 m × 9.8 m/s² (using the acceleration due to gravity). The smaller boy's torque, at an unknown distance x from the fulcrum, would be 40 kg × x m × 9.8 m/s². Setting these torques equal and solving for x gives us the position where the smaller boy must sit to balance the seesaw. With the seesaw in balance, the board's center of mass must be at the fulcrum. Therefore, the weight of the board acts directly on the fulcrum, not creating any torque, and its mass would not affect the equilibrium of the seesaw, meaning the mass of the board can be any value and still maintain balance provided the boys are positioned correctly.