Higher Physics - Unit 1 - Our Dynamic Universe

Scalar quantities

Quantities that only have magnitude (size) and no direction. Examples include distance, speed, time, frequency, energy, and mass.

Vector quantities

Quantities that have both magnitude (size) and direction. Examples include velocity, displacement, acceleration, and force.

Pythagoras' theorem

A theorem used to find the magnitude of a right-angled vector. It states that the square of the hypotenuse is equal to the sum of the squares of the other two sides.

Cosine rule

A rule used to find the magnitude of a non-right angled vector. It relates the sides and angles of a triangle.

Sine rule

A rule used to find the direction of a non-right angled vector. It relates the sides and angles of a triangle.

Components of a vector

Breaking down a vector into its horizontal and vertical components.

Equations of motion

Equations used to describe the motion of objects that are accelerating at a constant rate. They include equations for displacement, velocity, acceleration, and time.

Acceleration

The rate of change of velocity and is measured in meters per second per second (m/s^2).

Gradient of a graph

The slope of a graph, which represents the acceleration of an object.

Area under a graph

The area enclosed by a graph, which represents the displacement of an object.

Newton's Laws of Motion

Three laws that describe the relationship between forces and motion.

Newton's First Law

An object at rest will stay at rest, and an object in motion will stay in motion at a constant speed in a straight line unless acted upon by an unbalanced force.

Newton's Second Law

The acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass.

Newton's Third Law

For every action, there is an equal and opposite reaction.

Weight

The downward force on an object due to gravity, calculated as the product of mass and acceleration due to gravity (W = mg).

Friction

The force that acts between surfaces when they rub together, always acting in the opposite direction to the relative motion between the surfaces.

Air resistance

The force that acts against an object as it moves through the air.

Tension

The pulling force of a string, rope, cable, or chain.

Reaction force

The force of contact from a surface, always acting at right angles to the surface.

Resultant force

A single force that has the same effect as the combination of multiple forces acting on an object.

Terminal velocity

The velocity at which the forces on a falling object become balanced.

Law of Conservation of Momentum

The total momentum before an interaction between objects is equal to the total momentum after the interaction, provided there are no external forces acting on the objects.

Elastic collision

A collision in which both momentum and kinetic energy are conserved.

Inelastic collision

A collision in which momentum is conserved, but kinetic energy is not conserved.

Impulse

The product of force and time, or the change in momentum of an object during an interaction.

Newton's Third Law of Motion

The forces acting on two objects in a collision are equal in size and opposite in direction.

Projectile

An object that is in free fall, with the only force acting on it being gravity.

Horizontal motion

The motion of a projectile in the horizontal direction, which is at a constant velocity.

Vertical motion

The motion of a projectile in the vertical direction, which has a constant downward acceleration.

Satellite

An object that is in free fall around a star or planet, but has enough horizontal velocity to never reach the surface.

Gravitational force

The force experienced by an object with mass in a gravitational field, dependent on the mass of the object and the gravitational field strength.

Weight

The gravitational force acting on an object.

Universal Law of Gravitation

The law that calculates the gravitational force between two objects, using the Universal Constant of Gravitation.

Inverse square law

The size of the gravitational force varies with the inverse square of the distance between the centers of masses of the objects.

Mutual force

The gravitational force between two objects is equal and opposite in direction.

Special Relativity

Albert Einstein's theory that explains the behavior of objects traveling at speeds approaching the speed of light.

Time dilation

The apparent increase in time of events on an object moving relative to an observer.

Length contraction

The apparent decrease in length of an object moving relative to an observer in the direction of travel.

Doppler Effect

The shift in wavelengths of sound and light as a source moves relative to an observer.

Redshift

The shift to longer wavelengths of light from objects moving away from us.

Blueshift

The shift to shorter wavelengths of light from objects moving towards us.

Hubble's Law

The relationship between the redshift and distance of distant galaxies, suggesting that the universe is expanding.

Hubble's constant

The value used to estimate the age of the universe based on Hubble's Law.

Dark matter

The unaccounted-for matter in galaxies, estimated based on the orbital speed of stars within them.

Dark energy

The unknown force that is causing the rate of expansion of the universe to increase.

Black-body radiation curve

A graph that shows the distribution of emitted radiation over a wide range of wavelengths, with a characteristic shape.

Peak wavelength

The wavelength at which the emitted radiation in a black-body radiation curve is at its highest point.

Hubble's Law

The observation that distant galaxies are moving away from us, indicating that the universe is expanding.

Cosmic Microwave Background Radiation (CMBR)

Microwave radiation detected from all directions in space, which is believed to be leftover radiation from the early stages of the universe.