DOST-SEI Mechanical-Technical Review

Vocabulary practice flashcards covering mechanical-technical concepts, Newton's laws of motion, projectile mechanics, work and energy, fluid statics, thermodynamics, acoustics, and mechanical tools.

Mechanical-Technical Reasoning

The ability to comprehend and apply concepts related to mechanics, physics, machinery, and technology by analyzing tools, equipment, forces, motion, and mechanical systems.

Newton's First Law (Law of Inertia)

The principle stating that an object at rest stays at rest and an object in motion continues in motion with constant velocity unless acted upon by an external net force.

Newton's Second Law (Law of Acceleration)

The law stating that the acceleration of an object is directly proportional to the net force acting upon it and inversely proportional to its mass, defined by the formula $F = ma$.

Newton's Third Law (Law of Action and Reaction)

The principle stating that for every action, there is an equal and opposite reaction, meaning forces always occur in matched interaction pairs.

Projectile Motion

The motion of an object launched into the air that follows a curved parabolic trajectory under the sole influence of gravity, consisting of independent constant horizontal velocity and constant vertical acceleration.

Horizontal Range ($R$)

The total horizontal distance covered by a projectile landing at the same level from which it was launched, represented by $R = \frac{v_0^2 \sin(2\theta)}{g}$.

Potential Energy

Stored energy possessed by an object as a result of its position, condition, or configuration.

Gravitational Potential Energy ($U_g$)

The energy stored in an object due to its vertical position or height above the ground, determined by the formula $U_g = mgh$.

Elastic Potential Energy ($U_e$)

The energy stored as a result of deforming an elastic object, such as stretching or compressing a spring, given by $U_e = \frac{1}{2}kx^2$.

Kinetic Energy ($K$)

The energy that an object possesses because of its motion, proportional to its mass and the square of its speed, defined by $K = \frac{1}{2}mv^2$.

Conservation of Mechanical Energy

The principle stating that in the absence of non-conservative forces such as friction, the total mechanical energy of a system ($E_{\text{mechanical}} = \text{PE} + \text{KE}$) remains constant.

Lever Principle

The mechanical rule stating that a lever multiplies applied force through a pivot point (fulcrum) to ease work, achieving static equilibrium when the clockwise moment equals the counterclockwise moment.

Density ($\rho$)

An intensive physical property defining the mass per unit volume of a substance ($\rho = \frac{\text{mass}}{\text{volume}}$), quantified in SI units of $\text{kg/m}^3$.

Hydrostatic Pressure

The pressure exerted by a fluid at rest due to the force of gravity, represented by $P = h\rho g$, which increases linearly with depth.

Spurt Principle

The fluid behavior demonstrating that a liquid exit stream located at the deepest point of a container emerges at the highest velocity due to greater hydrostatic pressure.

Heat ($Q$)

Energy transferred between substances or systems as a consequence of a temperature gradient, flowing spontaneously from higher temperature to lower temperature.

Speed of Sound

The rate at which acoustic vibrations travel through a medium, moving slowest in gases ($\approx 343\,\text{m/s}$ in air), faster in liquids ($\approx 1{,}480\,\text{m/s}$ in water), and fastest in solids ($> 5{,}000\,\text{m/s}$ in steel).

Resonance

The wave phenomenon in which an oscillating system driven at its natural frequency undergoes a substantial increase in vibrational amplitude.

Diffraction

The bending and spreading of waves around obstacles or when propagating through narrow apertures.

Wave Interference

The phenomenon occurring when two or more waves overlap, combining constructively when in phase to increase amplitude or destructively when out of phase to decrease amplitude.

Doppler Effect

The perceived shift in frequency or pitch of a wave caused by relative motion between the source of the wave and the observer.

Socket Wrench

A mechanical ratcheting hand tool designed to fit over interchangeable sockets, used primarily to tighten or loosen hex bolts and nuts.