Mechanics is the branch of physics that deals with the behavior of objects under the influence of forces. Forces are external influences that cause an object to move, stop, or change direction. A force is measured in Newtons (N) and is defined by its magnitude, direction, and point of application. Torque is the measure of a force’s ability to cause rotational motion around an axis. It is calculated as the product of the force and the perpendicular distance from the axis of rotation, measured in Newton-meters (Nm). Friction is the resistive force that opposes the relative motion between two surfaces in contact. It depends on the nature of the surfaces and the normal force pressing them together. Stress is the internal resistance of a material to an applied force, defined as force per unit area and measured in Pascals (Pa). Strain is the measure of deformation or displacement that occurs in a material due to stress, represented as a dimensionless ratio of the change in length to the original length. Understanding these mechanical principles is essential for analyzing and designing structures, machines, and mechanical systems.