Final answer:
A rigid body is an object that does not deform under external forces. Equilibrium conditions for rigid bodies are applied to solve engineering problems. Rigid bodies also possess angular momentum, which is important in the design of rotating systems.
Step-by-step explanation:
A rigid body is an object that does not deform under the actions of external forces. When solving engineering problems, the equilibrium conditions for rigid bodies are applied. This means that the forces and torques acting on the rigid body must balance out so that the body remains in a state of equilibrium.
One practical implication of applying equilibrium conditions for a rigid body is the ability to choose any point as the origin of the reference frame. The choice of reference frame depends on the specific problem being solved. This allows for the mathematical form of the equilibrium conditions to be simplified and easily solved.
Rigid bodies also have angular momentum, which is crucial in the design of systems that involve rotation. Objects like planets, flywheels, and propellers possess angular momentum due to their spin or rotation around an axis. Understanding and calculating angular momentum is important in engineering and design.