PHY1210 (Mechanics) Practice Flashcards

Comprehensive vocabulary flashcards covering basic mechanics, kinematics, dynamics, rotational motion, and universal gravitation as presented in the PHY1210 lecture notes.

Mechanics

A branch of physics that deals with the study of the behaviour of objects in motion or at rest.

Statics

A sub-branch of mechanics that deals with the study of objects at rest which may be under the influence of forces.

Dynamics

A sub-branch of mechanics that deals with the study of objects in motion and the forces causing such motion.

Kinematics

A branch of mechanics that studies the behaviour of objects in motion without considering the force acting on them.

Physical Quantity

Any quantity that can be measured and consists of a magnitude and unit.

Fundamental Quantities

Physical quantities from which other physical quantities can be expressed; examples include length, time, mass, temperature, electric current, amount of substance, and luminous intensity.

Derived Quantities

Physical quantities that can be expressed in terms of the fundamental quantities.

Unit of Measurement

The standard used for the measurement of a physical quantity, which is universally accepted and does not change with time.

Metre (m)

The length of the path travelled by light in a vacuum during a time interval of $\frac{1}{299,793,458}$ of a second.

Second (s)

The duration of $9,162,631,770$ periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atoms.

Kilogram (kg)

The mass equal to the mass of the standard platinum-iridium alloy cylinder (90% platinum and 10% iridium) kept in Paris, France.

Ampere (A)

The current which, when flowing through two infinitely long straight conductors at a distance of $1\,m$ in vacuum, produces a force of $2 \times 10^{-7}\,N/m$ between them.

Kelvin (K)

Defined as $\frac{1}{273.16}$ part of the thermodynamic temperature of the triple point of water.

Mole (mol)

The amount of substance of a system containing as many elementary particles as there are atoms in $12\,g$ of carbon-12.

Candela (Cd)

The luminous intensity in a perpendicular direction of a surface of $\frac{1}{600,000}\,m^2$ of a black body at the temperature of freezing platinum under a pressure of $1.013 \times 10^5\,N/m^2$.

Dimensional Analysis

A means of simplifying a physical quantity in terms of the fundamental quantities; the dimension of a quantity is the power to which fundamental quantities are raised to express that quantity.

Principle of Dimensional Homogeneity

The view that all additive terms in a physical equation must have the same dimensions.

Scalar Quantity

Any quantity which has only magnitude but no direction, such as mass, volume, energy, or money.

Vector Quantity

Any quantity which has both magnitude and direction, such as displacement, velocity, acceleration, or electric field.

Position (x)

The location of a body with respect to a chosen reference point or frame that can be considered the origin of a coordinates system.

Displacement ($\Delta x$)

The change in position of a body in a specified direction, calculated as $\Delta x = x_f - x_0$.

Average Velocity

The change of displacement of a body divided by the change in time interval during the motion.

Instantaneous Velocity

The velocity of a body at any given instant of time, defined as $\lim_{\Delta t \rightarrow 0} \frac{\Delta x}{\Delta t} = \frac{dx}{dt}$.

Acceleration due to Gravity (g)

The acceleration caused by gravity, which does not depend on the nature of the material and has a value of approximately $9.81\,ms^{-2}$ acting vertically downward.

Relative Motion

Motion where more than one body is in motion and one examines the motion of one moving body relative to another.

Projectile

Any object thrown into the air and allowed to move under the influence of gravity and air resistance.

Trajectory

The path followed by a projectile, which is shown to be a parabola.

Horizontal Range (R)

The horizontal distance covered by a projectile from the point of projection to the point where it strikes the ground surface.

Force (F)

Any agent that can change the state of motion of an object.

Mass

The quantity of matter in a body which is constant everywhere and acts as a measure of the inertia of a body.

Weight (w)

The force of gravity acting upon an object, calculated as $w = mg$.

Inertia

The measure of the reluctance of a body at rest to move or its reluctance to stop while in motion.

Newton's First Law of Motion

States that an object at rest will continue to be at rest and an object in motion will continue to be in motion unless a non-zero force is applied on it.

Newton's Second Law of Motion

States that the force ($F$) is linearly proportional to the product of mass ($m$) and acceleration ($a$) of a body, expressed as $F = ma$.

Newton's Third Law of Motion

States that when two bodies interact, they apply forces (action and reaction) to one another that are equal in magnitude and opposite in direction.

Momentum (p)

The product of an object's mass ($m$) and its velocity ($v$), given by $p = mv$.

Impulse

The change in momentum of a body, also equal to the product of force and time interval ($Ft$).

Work (W)

Done when force is exerted on an object and the object moves; calculated as $W = \vec{F} \cdot \vec{x} = Fx\cos(\theta)$.

Kinetic Energy (K)

Energy of motion, given by $K = \frac{1}{2}mv^2$.

Potential Energy (P)

Stored energy, commonly gravitational potential energy, defined as $P = mgh$.

Mechanical Energy (E)

The sum of kinetic energy and potential energy ($E = K + P$).

Work-Energy Theorem

States that the work done by the net force on an object equals the change in the object’s kinetic energy.

Power (P)

The rate of doing work, calculated as $P = \frac{W}{t} = Fv$; measured in Watts (W).

Collision

Two objects coming into contact for a very short period involving a reciprocative interaction of momentum and energy.

Coefficient of Restitution (e)

The ratio of the magnitudes of the final relative velocity to the initial relative velocity after and before a collision.

Perfectly Elastic Collision

A collision in which there is no change in kinetic energy and the coefficient of restitution $e = 1$.

Inelastic Collision

A collision in which the kinetic energy decreases and the coefficient of restitution $e < 1$.

Totally Inelastic Collision

A collision in which the two objects stick together after the impact, resulting in a coefficient of restitution $e = 0$.

Center of Mass (C.M.)

A point where the whole mass of a body or system of particles appeared to be concentrated.

Uniform Circular Motion

Motion of a body in a circular path of constant radius at constant speed while the velocity direction changes continuously.

Angular Velocity (\omega)

The amount of angle turned in radians by a body in one second, given by $\omega = 2\pi f$.

Centripetal Acceleration ($a_r$)

The acceleration with which a body accelerates toward the center of motion in a circular path, defined as $a_r = \frac{v^2}{r}$.

Centripetal Force (F)

The force that keeps an object in a uniform circular motion, calculated as $F = \frac{mv^2}{r}$.

Banking of Road

The process of raising the outer edge of a curved road above the inner edge to provide safer turning for vehicles.

Moment of Inertia (I)

A measure of a rotating body's resistance to angular acceleration, defined for mass points as $I = \sum m_i r_i^2$.

Parallel Axis Theorem

States that $I = I_C + MR^2$, where $I_C$ is the moment of inertia about an axis through the center of mass and $R$ is the perpendicular distance to the parallel axis.

Radius of Gyration (K)

The radial distance to a point where, if the total mass were concentrated, the moment of inertia would be the same as the body's actual distribution.

Angular Momentum (L)

The product of the moment of inertia and angular velocity of a rotating body ($L = I\omega$).

Newton's Law of Universal Gravitation

States that every particle attracts every other particle with a force $F = \frac{Gm_1m_2}{r^2}$.

Universal Gravitational Constant (G)

A constant value of $6.67 \times 10^{-11}\,Nm^2/kg^2$.

Escape Velocity ($v_e$)

The minimum velocity required by an object to escape the gravitational pull of a planet, given by $v_e = \sqrt{2g_ER_E}$ for Earth.

Geosynchronous Satellite

A satellite that stays above the same point on Earth by having an orbital period equal to Earth's rotation period.

Kepler's First Law

Planets move on elliptical orbits about the sun with the sun at one focus.

Kepler's Second Law

The area per unit time swept out by a radius vector from the Sun to a planet is constant.

Kepler's Third Law

The square of a planet's orbital period is proportional to the cube of the major axis of the planet's orbit.