Final answer:
All of the provided statements regarding static equilibrium are true, highlighting the necessity of zero net torque about any axis of rotation and the ability to solve for unknown forces in a 2D system.
Step-by-step explanation:
The statements concerning static equilibrium in physics can be addressed as follows:
- It is true that when solving a static equilibrium problem, it is necessary to identify the direction (sign) of the torque produced by each individual force.
- Another true statement is that if a system is in static equilibrium, the net torque is zero about any axis of rotation. This underlines the concept of static equilibrium in physics.
- The statement that a system is in static equilibrium if the net torque is zero is also true because equilibrium not only requires that the net force, but also that the net torque be zero.
- For a 2D (two-dimensional) problem, it is true that the equilibrium equations can solve for three or fewer unknown forces, reflecting the two components of the net force being zero along with the net torque being zero in a planar system.
In summary, all the provided options accurately reflect the principles of static equilibrium in the context of solving physics problems.