Physics Unit 3

Vector

A vector is a mathematical object used in physics and math to represent magnitude and direction. It describes quantities like displacement, velocity, and force. Vectors can be shown as arrows, where length represents magnitude and direction represents direction. They can also be represented algebraically using coordinates or components.

Resultant vector

The resultant vector is the sum or combination of two or more individual vectors. It is found by adding or subtracting the individual vectors using vector addition or subtraction. The magnitude and direction of the resultant vector depend on the magnitudes and directions of the individual vectors.

Impact velocity

Impact velocity refers to the velocity at which an object strikes or collides with another object. It is a measure of the speed at which the impact occurs. The impact velocity can have significant effects on the outcome of the collision, such as the amount of damage caused or the transfer of energy. It is commonly used in physics and engineering to analyze and predict the behavior of objects during collisions.

Resolution (vector)

In vector context, resolution determines magnitude and direction by breaking down a vector into components along axes. Trigonometry and vector addition/subtraction are used to determine vector resolution.

Elevation angle

The angle at which a projectile is launched, with respect to the horizontal.

Free-fall acceleration

Acceleration of a body falling freely in a vacuum near the surface of an astronomical body in the local gravitational field.

Combine (vectors)

Add two or more vectors to determine the resultant vector.

Impact speed

Speed at which an object impacts the surface.

Launch velocity

Velocity at which a projectile is launched: has magnitude and direction, specified as angle of elevation to the horizontal.

Force

Push or pull between objects which can cause a change in speed, direction of motion or changing the shape.

Weight

Measure of force of gravity acting on object (Fw, Newtons, N).

Mass

Object’s resistance to change in motion or amount of matter in object (m, kilogram, kg).

Normal force

Force acting along imaginary line that is drawn perpendicular to the surface.

Friction

Resistance to motion of surface moving relative to another.

Tension

Pulling force transmitted along rope, string, cable or chain on an object.

Applied force

Force applied to an object by a person or another object.

Uniform circular motion

Motion of an object travelling at a constant speed in a circle.

Centripetal force

Force acting on an object travelling in a circle that constantly pulls or pushes the object towards the centre of motion (F, newton, N)

Centripetal acceleration

Acceleration experienced by any object moving in a circular path, directed towards centre of motion (ac, metres/s²).

Period

Time taken to complete one revolution: time/no of revolutions: (T, second, s)

Tangential velocity

Linear velocity of object undergoing circular motion where magnitude is speed of object and direction is a tangent to circular path at moment.

Rotational speed

Number of revolutions an object does per second: different to linear speed.

Gravity

Force of attraction between objects with mass.

Newton’s law of universal gravitation

Force of attraction between each pair of point particles is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Gravitational field

Region of space surrounding a body in which another body experiences force of gravitational field.

Gravitational field direction

Towards the direction of the net gravitational force.

Gravitational field strength

(G) is net force (F) per unit mass (m) at particular point in gravitational field.

First law of planetary motion (law of orbits)

All planets move about the sun in elliptical orbits, having the sun as one of their foci

Second law of planetary motion (law of areas)

A radius vector joining any planet to the sun sweeps out equal areas in equal lengths of time.

Third law of planetary motion (law of periods)

Square of the sidereal period of a planet is directly proportional to the cube of its mean distance from the sun.

Sidereal period

Time taken for planet to complete one orbit of another body, relative to the stars.

Synodic period

Time taken for planet to appear in front of the same constellation of stars as seen from Earth.

Coulomb’s law

Like electric charges repel and opposite electric charges attract, with a force proportional to the product of the electric charges and inversely proportional to the square of the distance between them.

Coulomb’s law constant, k

Constant of proportionality relating forced between charged objects to the magnitude of their charge and separation distance.

Electric field

Region of space near an electrically charged particle or object within which a force would be exerted on other electrically charged particles or objects.

Electric field strength

Intensity of electric field at a particular location (E, newton per coulomb, N/C)

Uniform electric field

A field that has a constant field strength, as found between charged parallel plates.

Electric potential energy

Capacity of electric charge carriers to do work due to their position in electric field (W, joules, J)

Electric potential

The electrostatic potential energy stored per unit charge at any given point (V, volts, V)

Electrical potential difference

Work done in moving a unit chagre between final and initial positions in an electric field (V, Volt, V)

Magnetism

Phenomenon associated with magnetic fields which arise from motion of electric charges.

Magnetic field line

Direction an isolated north pole would move in the field.

Ampere’s right hand rule

Field around the wire: thumb represents current (I), finger curls represent direction of magnetic field lines (B).

Tesla

SI unit of magnetic field strength, 1T = 1 N/C m/s

Solenoid

Long straight coil of wire used to generate a controlled and almost uniform magnetic field.

Fleming’s left hand rule

Direction of force on current-carrying wire: Thumb represents direction of force on wire (F), pointer finger represents magnetic field (B), middle finger represents direction of current (I)

Magnetic flux

Measurement of the total magnetic field that passes through a given area (weber, Wb)

Magnetic flux density

Strength of a magnetic field or number of magnetic field lines per unit area (B, weber per square mere, Wb/m² or T)

Electromagnetic induction

Production of electromotive force or voltage across electrical conductor due to dynamic interaction with a magnetic field.

Electromotive force

A difference in potential that tends to give rise to an electric current (V).

Faraday’s law

When the magnetic flux linking a circuit changes, an EMF is induced in the circuit that is proportional to the rate of change of the flux linkage.

Lenz’s law

Direction of an induced electric current is such that it produced a current whose magnetic field opposes the change in the circuit or the magnetic field that produces it.

Fleming’s right hand rule

Same as Fleming’s left hand rule but used to determine direction of induced current.

Mutual induction

Production of EMF in a circuit by a change in the current of an adjacent circuit that is linked to the first by the flux lines of a magnetic field.

Transformer

Device that transfers alternating current from one circuit to another, usually stepping up or stepping down the voltage.

Electromagnetic wave

Waves produced by an oscillating electric charge that radiates out at the speed of light as mutually perpendicular electric and magnetic fields.

Transverse waves

Wave where direction of oscillation of particles is perpendicular to direction of energy transfer.