Final answer:
In physics, pivoting refers to rotational motion and moments of force. By choosing a specific pivot point, the forces and torques in a system can be balanced. The equilibrium condition for torques in rotation about the chosen pivot point is used to solve the problem.
Step-by-step explanation:
In physics, when we talk about pivoting, we are usually referring to rotational motion and moments of force.
The pivot point is the point around which an object rotates or pivots. In Example 12.1 and Example 12.6, the question asks us to choose a specific pivot point and perform the pivoting.
The pivot location determines how the forces and torques are balanced in the system.
By choosing a specific point as the pivot, we can simplify the calculations and solve the problem. In these examples, the pivot is chosen at the rear axle and at the center of mass, respectively.
To solve the problem, we use the equilibrium condition for torques in rotation about the chosen pivot point.
This condition states that the sum of the torques acting on an object must be zero for it to be in rotational equilibrium.