Engineering Mechanics: Statics Practice Flashcards

These vocabulary flashcards cover the foundational concepts, definitions, and principles of Statics and Engineering Mechanics based on the lecture modules.

Engineering Mechanics

The branch of applied science and physics that studies how physical bodies respond when subjected to forces, motion, or internal bodies.

Rigid-Body Mechanics

A branch of engineering mechanics that assumes the object does not deform or change shape under external forces.

Statics

A branch of mechanics dealing with bodies at rest or moving at a constant velocity, where the forces acting on the system are balanced ($\Sigma F = 0$).

Dynamics

A branch of mechanics dealing with accelerated motion, further divided into kinematics and kinetics.

Kinematics

The analysis of motion, including position, velocity, and acceleration, without considering the forces causing it.

Kinetics

The analysis of the forces that cause motion, expressed by the equation $\Sigma F = ma$.

Force ($F$)

A push or pull acting on a body, measured in Newtons or pound-force, characterized by both magnitude and direction.

Moment / Torque ($M$)

The tendency of a force to rotate a body around a point or axis.

Support Reactions

The constraining forces exerted by supports (such as pins, rollers, or fixed points) that prevent a structure from moving.

Free-Body Diagram (FBD)

A visual sketch showing a simplified object isolated from its surroundings, with every external force, moment, and reaction force explicitly drawn as vectors.

Translational Equilibrium

A condition where the vector sum of all exerted forces acting on a body must equal zero ($\Sigma F = 0$).

Rotational Equilibrium

A condition where the vector sum of all external moments acting on the body about any point must equal zero ($\Sigma M = 0$).

Rigid Body

An idealized solid object in which the distance between any two given points remains completely constant, regardless of the external forces applied to it.

Concurrent Force System

A system where the lines of action of all forces pass through a single common point, resulting in zero net movement about that point ($\Sigma M = 0$).

Non-Concurrent Force System

A system where force lines of action do not meet at a single point and are not parallel, causing both translation and rotation.

Parallel Force System

A system where the lines of action of all forces are parallel to each other, which can be 'like' (same direction) or 'unlike' (opposite directions).

Scalar Quantity

A quantity completely defined by its magnitude (size, amount, or distance) and a unit, having no direction.

Vector Quantity

A quantity that requires both a magnitude and a specific direction in space to be fully understood.

Principle of Transmissibility

States that the external effect of a force on a body remains the same for all points of application along its line of action.

Resultant

A single force or combination of force and couple that produces the exact same translational and rotational effects as an original system of multiple forces.

Parallelogram Law

A foundational axiom stating that the resultant of two forces acting at a point is represented by the diagonal of a parallelogram formed by the two forces as adjacent sides.

Triangle Law of Forces

If two forces acting at a point be represented in magnitude and direction by two sides of a triangle taking in order their resultant may be represented in magnitude and direction by the third side of triangle taken in opposite order

External Forces

Actions of other bodies on the structure under consideration, classified as applied forces (loads) and reaction forces.

Internal Forces

Forces and stresses (such as compression, tension, bending, shear, and torsion) that develop within an object to resist deformation and maintain stability.

Applied Forces

are the live loads and environmental loads are usually known the analysis

Coplanar Force System

A force system where all individual forces act within a single plane (2D).

Non Coplanar

Also called as a spatial force system when all forces do not lie or act on one plane(3D).

Varignon's Theorem

Also known as the Principle of Moments, it states that the moment of the resultant force about any point is equal to the sum of the moments of its individual component forces about that same point ($M_R = \Sigma M_i$).

Couple

A system of two equal, parallel forces acting in opposite directions that creates a twisting effect but has a weight resultant of zero.

Centroid

The geometric center of a figure, shape, or object, representing the average position of all points and acting as its center of mass or balance point.

Beam

a structural element that primarily resists loads applied laterally (sideways) to its axis

Rectangular Frames

A rectangular frame consists of horizontal beams and vertical columns rigidly joined together in a skeletal rectangle

Truss

A structural element composed of straight members connected at joints to form a web of triangles, providing strength and rigidity.

Stable Equilibrium

A state where an object returns to its original position after displacement, characterized by the center of gravity rising slightly when moved.

Unstable Equilibrium

A state where an object moves further away or falls over after displacement, with the center of gravity lowering as the object tips.

Neutral Equilibrium

A state where an object stays in its new position after displacement, with the center of gravity remaining at the same height.