Physics Lecture Review on Energy, Momentum, and Waves

Vocabulary terms and definitions covering mechanics, energy conservation, electromagnetism, oscillations, and wave optics based on the lecture notes.

Work of a constant force

Calculated using the formula $W_F = F \times d \times \text{cos}(F, d)$, where a resistive force results in $W_{fr} = -fr \times d$ and gravity does work $W_{mg} = mg(h_i - h_f)$.

Average Power ($P_{\text{av}}$)

The rate of work done over a period of time, expressed as $P_{\text{av}} = \frac{\text{d}W}{\text{d}t} = F \times V_{\text{av}}$.

Moment of inertia ($I$)

A measure of an object's resistance to rotational acceleration; for a particle, it is defined as $I = mr^2$ with units in $\text{kg m}^2$.

Newton's 2nd Law (Translation vs. Rotation)

In translation, \text{∑} F = ma. In rotation, the equivalent is \text{∑} M_F = I\theta", where $M_F$ is the moment of force and $\theta"$ is angular acceleration.

Work-Energy Theorem

States that the change in kinetic energy is equal to the sum of the work done by all forces: \text{Δ}K.E = \text{∑}W.

Law of non-conservation of M.E

States that the change in mechanical energy is equal to the work done by non-conservative forces: \text{Δ}ME = \text{∑}W_{\text{non-conservative forces}}.

Linear Momentum ($P$)

The product of a particle's mass and its velocity: $P = mv$, measured in $\text{kg m/s}$.

Elastic Collision

A collision where both linear momentum and kinetic energy are conserved ($K.E_{\text{bef}} = K.E_{\text{aft}}$).

Angular Momentum ($L$)

The rotational equivalent of linear momentum, measured in $\text{kg m}^2/\text{s}$, where for a system \text{∑} M_F = I\theta".

Periodic Motion

Motion that repeats itself identically during a constant interval of time $T$, called the period.

Rectilinear Sinusoidal Motion (R.S.M)

A to and fro periodic motion represented by the abscissa equation $x = x_m\text{sin}(\text{w}t + \text{Ø})$.

Differential Equation of an Oscillator

A second-order differential equation for an undamped system in the form $x" + \text{w}_0^2x = 0$, where $\text{w}_0^2 = \frac{k}{m}$.

Lenz's Law

States that the direction of the induced current is such that its electromagnetic effects always oppose the cause creating it by Electromagnetic Induction (E.M.I).

Faraday's Law

States that the induced e.m.f ($e$) at any instant is equal to the negative derivative of the magnetic flux with respect to time: $e = -\frac{\text{d}\text{Ø}}{\text{d}t}$.

Self-Induction

A phenomenon where a coil delays the establishment of current; the coil acts as a source of self-induced e.m.f expressed as $e = -L\frac{\text{d}i}{\text{d}t}$.

Magnetic Energy stored in a coil

The energy stored in an inductor's magnetic field, calculated as $E_L = \frac{1}{2}Li^2$.

Capacitance ($C$)

The ability of a capacitor to store charge ($q$) for a given voltage ($u_c$), defined as $C = \frac{q}{u_c}$ and measured in Farad ($\text{F}$).

Mechanical Wave

A wave that requires a material medium to propagate, such as water waves or sound waves.

Monochromatic light

Light consisting of a single wavelength, corresponding to a single frequency and a single color, such as a laser.

Dispersion of light

The phenomenon in which white light separates into its constituent wavelengths (colors) when passing through a medium where the refractive index depends on the wavelength.

Diffraction

A deviation in the direction of light (without reflection or refraction) when it crosses a thin slit, sharp edge, or narrow aperture ($a < 1\text{ mm}$).

Angular width of a central fringe ($2\text{±}_1$)

In a diffraction pattern, for small angles, the angular width is defined as $2\text{±}_1 = \frac{2\text{λ}}{a}$, where $\text{λ}$ is the wavelength and $a$ is the slit width.