Physics Flashcards

Flashcards based on Physics lecture notes for exam review.

Average Speed

Total distance traveled divided by total time taken.

Formula for Average Speed

v=s/t

Acceleration

The rate of change of an object’s velocity.

Velocity

The speed of an object in a stated direction.

Vector Quantity

Has both magnitude (size) and direction.

Scalar Quantity

Has magnitude but no direction.

Finding Distance Traveled

Distance=area under speed-time graph

Area Rectangle

Width x height.

Area Triangle

½ x base x height.

Calculating Acceleration

acceleration=change in velocity/time taken

Forces

The action of one body on a second body; unbalanced forces cause changes in speed, shape or direction; measured in Newtons.

Weight Force

The pull of gravity; acts vertically downwards.

Friction

Force that acts when two surfaces rub over one another, opposing motion.

Air Resistance or Drag

Force of friction acting on an object moving through air or liquid; increases with speed of motion.

Upthrust

Upward push of a liquid or gas on an object.

Solid Friction

Resistance to motion caused when two surfaces are in contact.

Resultant Force

Single force that has the same effect on a body as two or more forces; can change both speed and direction.

Gravity

Force that exists between any two objects with mass.

Formula Weight

W=m x g -> gravitational field strength is 9.8N/kg

Mass

Measured in kg; tells you how much matter the object is composed of.

Weight

Measured in N; tells you the gravitational force that acts on the object.

Terminal Velocity

Greatest speed reached by an object when moving through a fluid.

Force, Mass, and Acceleration Formula

F=m x a

Impulse

Change in an object's momentum or the force acting on an object multiplied by the time for which the force acts.

Momentum

Quantity mass x velocity. P=m x v

Collision

Meeting of particles or bodies in which each exerts a force upon the other.

Principle of Conservation of Momentum

Total momentum is constant and does not change because of an interaction between bodies.

Turning Effect

When a force causes an object to rotate or would make the object rotate if there were no resistive forces.

Moment

Turning effect of a force about a pivot, given by force x perpendicular distance from the pivot.

Principle of Moments

When an object is in equilibrium, the anticlockwise and clockwise moments are equal.

Extension

Increased length of an object when a load is attached to it.

Hooke's Law

Spring constant=force/unit extension

Pressure

Force acting per unit area at right angles to a surface.

Pressure Formula

Pressure=force/area

Energy

Quantity that must be changed or transferred to make something happen.

Kinetic Energy

Energy stored of a moving object.

Gravitational Potential Energy

Energy store of an object raised up.

Chemical Energy

Energy stored in bonds between atoms that can be released when chemical reactions take place.

Nuclear Energy

Energy stored in the nucleus of an atom

Strain/Elastic Energy

Energy stored in the changed shape of an object.

Internal Energy

The energy of an object; the total kinetic and potential energies of its particles.

Thermal Energy

Energy transferred from a hotter place to a colder one because of the difference in temperature.

Conservation of Energy

Energy cannot be created or destroyed; it can only be transferred or stored.

Efficiency

Fraction of energy supplied that is usefully transferred.

Non-Renewable Resource

An energy resource that is gone forever once it is used.

Renewable Resource

An energy resource that will be replenished (replaced) naturally when used.

Nuclear Fusion

Process by which energy is released when two small light nuclei join together to form a new heavier nucleus.

Work Done

Amount of energy transferred when one body exerts a force on another; the energy transferred by a force when it moves. Work=force x distance moved IN THE DIRECTION OF THE FORCE.

Power

Rate at which work is done, or the rate at which energy is transferred.

Kinetic Particle Model of Matter

A model in which matter consists of moving particles.

Brownian Motion

Motion of small particles suspended in a liquid or gas, caused by molecular bombardment.

Attractive Forces

Forces between particles which hold the particles in fixed positions in a solid.

Kelvin Temperature Scale

Temperature measured from absolute zero.

Specific Heat Capacity

Energy required per unit mass per unit temperature increase.

Thermal Conduction

Transfer of thermal energy by the vibration of molecules.

Thermal Conductor

Substance that conducts thermal energy.

Thermal Insulator

Substance that conducts very little thermal energy.

Convection

Transfer of thermal energy through a material by the movement of the material itself.

Convection Current

Transfer of thermal energy by the motion of the fluid.

Infrared Radiation

Electromagnetic radiation with a wavelength greater than that of visible light; sometimes known as thermal energy.

Sound

Sounds are a series of vibrations which pass through the air or another material.

Compression

When the right-hand prong moves forward, it will squash the particles together, this makes the region become more dense.

Rarefaction

As the prong moves back to its original position, air particles will spread out and the density presented on the region will be less.

Measure Distance of Storm

Measure the time between lightning and thunder then divide that number by 3.

Amplitude

Greatest height or depth of a wave from its undisturbed position.

Frequency

Number of complete cycles of vibrations or waves per unit time; measured in hertz (1Hz=1 wave per second).

Ultrasound

Any sounds with a frequency higher than 20 000 Hz.

Sonar

Method used to measure the depth of water or locate an underwater object.

Reflection

Change of direction of a ray when it strikes a surface without passing through it.

Incident Ray

Ray of light arriving at a surface.

Reflected Ray

Ray of light which has been reflected from the surface.

Angle of Incidence

Angle between the incident ray and the normal drawn at the point where the ray hits the surface.

Angle of Reflection

Angle between the reflected ray and the normal drawn at the point where the ray hits the surface.

Normal

Line drawn at right angles to a surface at the point where a ray hits the surface.

Real Image

Image that can be formed on a screen.

Virtual Image

Image that cannot be formed on a screen.

Refraction

Bending of light when it passes from one medium to another.

Angle of Refraction

Angle between a refracted ray and the normal to the surface at the point where it passes from one medium to another.

Refractive Index

Measure of how much light slows, or how much it is bent.

Internal Reflection

When a ray of light strikes the inner surface of a material and some of it reflects back inside.

Critical Angle

Minimum angle of incidence at which TIR occurs.

Converging Lens

A lens that causes rays of light parallel to the axis to converge at the principal focus; fatter in the middle.

Diverging Lens

A lens that causes rays of light parallel to the axis to diverge from the principal focus; thinner in the middle then at edges.

Transverse Wave

A wave in which the vibration is at right angles to the direction of propagation of the wave.

Longitudinal Wave

A wave in which the vibration is forward and back, parallel to the direction of the propagation of the wave.

Diffraction

When a wave spreads out as it travels through a gap or past the edge of an object.

Electromagnetic Spectrum

Family of transverse waves; can be reflected, refracted, or diffracted; travel at the same speed; different frequencies, and have different effects.

Static Electricity

Electric charge held by a charged insulator.

Electrostatic Charge

Property of an object that causes it to attract or repel other objects with charge.

Electric Field

Region of space in which an electric charge will experience a force.

Current (I)

The rate at which electric charge passes a point in a circuit.

Ammeter

A meter for measuring electric current (amperes)

Voltage

The energy transferred or work done per unit charge.

Electromotive force (e.m.f)

The electrical work done by a source in moving charge around a circuit.

Resistance (Ω)

A measure of how difficult it is for an electric current to flow through a device or a component in a circuit.

Light-Dependent Resistor (LDR)

A resistor whose resistance changes depending on the amount of light received.

Thermistor

A resistor whose resistance depends on its environment, and depends on the temperature.

NTC Thermistor

A resistor whose resistance decreases with the increase in temperature.

Diode

An electrical component that allows the electric current to only flow one direction.

Light-Emitting Diode (LED)

A diode that emits light when current flows through it.