Final answer:
The question involves high school level physics, focusing on rotational motion, static equilibrium, and forces like friction and those exerted by a person. Calculations would require the value of the coefficient of static friction and other specifics concerning forces and torques.
Step-by-step explanation:
The student's question relates to analyzing the rotational motion and static equilibrium of a plank and calculating the related forces. Given the complexity of the topic, this is likely a high school-level physics problem. For a plank resting on joists or a surface, the frictional force could be determined by multiplying the coefficient of static friction by the normal force. However, precise calculations would require additional information such as the coefficient of friction and the angle of inclination if any.
To understand rotational motion, one must consider both torque and the moment of inertia. An example would be calculating the angular velocity of a stick with masses on either end as it rotates about an axis through its center. For static equilibrium, forces and torques must be balanced, which can involve analyzing the forces acting at various points along the plank, such as the forces exerted by a person carrying a plank.