Engineering Mechanics

Forces, moments and motion — the physics every machine obeys. The foundation of mechanical engineering: forces and their resultants, moments and couples, equilibrium and free-body diagrams, friction, centroids and moments of inertia, and the kinematics and dynamics of moving bodies.

• Force — A force is a push or pull with magnitude, direction and point of application. Learn force as a vector, units, resolving into components, adding forces to find a resultant, and solving concurrent force systems with Lami's theorem.
• Moment — A moment is the turning effect of a force about a point. Learn M = F·d, sign conventions, Varignon's theorem, couples, and how levers and spanners multiply force.
• Equilibrium — A body in equilibrium has no net force and no net moment. Learn free-body diagrams, support types and their reactions, solving beam and bracket reactions, and shear-force and bending-moment diagrams.
• Friction — Friction resists sliding between surfaces. Learn static and kinetic friction, the coefficient of friction, angle of friction, inclined planes, belt and rope friction, and where engineers want more or less friction.
• Centroid — The centroid is the geometric centre of an area or volume; the centre of gravity is where weight acts. Learn integral and composite-area methods, standard shape centroids, and why centroids matter for beams, stability and loads.
• Moment of Inertia — Area moment of inertia measures a section's resistance to bending; mass moment of inertia measures resistance to angular acceleration. Learn standard formulas, the parallel-axis theorem, polar moment, radius of gyration and section design.
• Kinematics — Kinematics describes motion without asking what causes it. Learn displacement, velocity and acceleration, the constant-acceleration equations, motion graphs, projectiles and rotational kinematics.
• Dynamics — Dynamics explains why motion happens. Learn Newton's laws, F = ma, work–energy and power, impulse–momentum, rotational dynamics T = Iα, and how they size motors, brakes and lifting systems.