Physics Flashcards
What does a scalar quantity have?
A scalar quantity has magnitude but no specific direction.
What does a vector quantity have?
A vector quantity has both magnitude and specific direction.
What is the difference between a scalar and a vector quantity?
A vector quantity has both magnitude and specific direction but a scalar quantity had just magnitude.
What do scalar quantities include?
Density, Time, Energy, Resistance, Speed, Volume, Mass, Power
What do vector quantities include?
Velocity, Force, Acceleration, Weight, Momentum
What is Distance?
Distance is a scalar quantity that referes to how much ground an object has covered during its motion
What is Displacement?
Displacement is a vector quantity that refers to how far out of place an object is from it’s starting position, it is the objects overall change in position.
What is velocity?
Velocity is speed in a stated direction
How do you work out speed?
Speed = distance/time
How do you work out the distance travelled?
distance travelled = average speed x time
How can speed be determined?
Speed can be determined by analysis of the gradient of distance/time graphs
True or False? There are typical speeds encountered in everyday experience for wind and sound, and for walking, running, cycling and other transportation systems?
True
How is weight defined?
weight = mass x gravitational field strength (W = M x G)
True or False? Weight is a force?
True and it is correctly measured in newtons.
How is weight measured?
In Newtons
What is gravitational field strength affected by?
Distance
What is there a relationship between?
The weight of a body and the gravitational field strength acting upon it.
Why is acceleration proportional to Force and Mass?
As we increase the force on an object the acceleration increases proportionally. The mass does not change as the acceleration increases.
What is Newtons first law of motion?
An object at a constant velocity will remain at the same velocity unless acted on by a resultant force
True or false? In all system changes energy is dissipated so that it is stored in less useful ways
True
How can unwanted energy transfers be limited?
Unwanted energy transfers can be limited by methods including through lubrication, thermal insulation
What is the equation to work out efficiency?
Efficiency = (useful energy output) / (total energy input)
How can efficiency be increased?
Efficiency can be increased by minimising unwanted energy transfers
True or false? Waves transfer energy and information without transferring matter
True
How can waves be described?
Waves can be described by the use of the terms frequency and wavelength. Waves can also be described by the terms, amplitude, period and wave velocity
True or false? There is a difference between longitudinal and transverse waves
True
How can wave speed be calculated?
Waves speed can be calculated by using the equation: wave speed = frequency x wavelength or wave speed = distance/time
How is the speed of air and water waves affected?
The speed of air and water waves is affected by the density of the medium through which they pass
How do you work out the velocity of the speed of sound in air?
speed of sound = distance/average time
What is the definition of frequency?
The number of waves past a given point per second, measured in hertz
What is the definition of wavelength?
The distance between two identical points on successive waves (such as peak to peak or trough to trough)
What is the definition of amplitude?
The maximum displacement of the wave
What is the definition of peak?
The maximum positive displacement
What is the definition of trough?
The maximum negative displacement
What do energy diagrams represent?
Energy transfers
True or false? Energy cannot be created or destroyed.
True
True or False? Where there are energy transfers in a closed system there is no change to the total energy in that system.
True
What is meant by conservation of energy?
For any closed system, energy is always conserved during every transfer
How can ray diagrams be described?
Reflection, refraction and total internal reflection, can be described with ray diagrams
What is the difference between specular and diffuse reflection?
A specular reflection is the light reflected from a smooth surface at a definite angle and a diffuse reflection is the light reflected from a rough surface and tends to reflect light in all directions
What is the colour of light related to?
It is related to the differential absorption at surfaces and the transmission of light through filters
Do processes convert wave disturbances between sound waves and vibrations in solids?
Yes and these processes can be used to explain the way the human ear works
What are sounds with frequencies greater than 20,000 hertz known as?
Ultrasound
What are sounds with frequencies less than 20 hertz know as?
Infrasound
What can ultrasound and infrasound be used for?
Sonar and foetal scanning
How are ultrasound and infrasound used?
They are used for exploration of the Earth’s mantle and core
What are electromagnetic waves?
They are transverse, that they at the same speed in a vacuum
From where do electromagnetic waves transfer energy?
all electromagnetic waves transfer energy from source to observer
What can out eyes see of electromagnetic radiation?
Our eyes can only detect a limited range of frequencies of electromagnetic radiation
Do different substances have different effect on the velocities of electromagnetic waves?
Yes
What are the main groupings of the continuous electromagnetic spectrum?
(In order) Radio waves, Microwaves, Infrared, Visible (including the colours of the visible spectrum), ultravoilet, X-rays and Gamma rays
What is the electromagnetic spectrum?
The electromagnetic spectrum as continuous from radio waves to gamma rays and the radiations within it can be grouped in order of decreasing wavelength and increasing frequency.
What happens to electromagnetic waves in ways that very with wavelength?
Different substances may absorb, transmit, refract, or reflect electromagnetic waves in ways that vary with wavelength
How can resultant forces be calculated?
Resultant forces can be calculated by subtracting the forces of adding them e.g. If the right side has a force of 8N and the left side has a force of 2N then it would be 6N to the right.
How can energy be transfered?
Heating, Waves, Electric Current, A force moving an object.
How do humans hear?
First, sound waves enter the ear canal. The eardrum is a thin membrane. Sound waves make it vibrate. Vibrations are passed on to tiny bones which amplify the vibrations. Vibrations are passed on to the liquid inside the cochlea. Tiny hairs inside the cochlea detect these vibrations and create electrical signals called impulses. Impulses travel along neurones in the auditory nerve to reach the brain.
What is the human hearing range?
Humans can only hear sounds between 20Hz and 20,000Hz. This is called the human hearing range. Sounds with a frequency above the human hearing range are ultrasounds. Sounds with a frequency below the human hearing range are infrasound
What are some of the terms used to describe the things inside the human ear?
The pinna is the actual ear. The auditory canal is a tunnel where sounds travel through. The eardrum is at the end of the tunnel. The ossicles is the bone attached to the ear drum. The oval window is an oval shaped bone attached to the ossicles. The semi-circular canals is attached to the oval window. The cochlea is attached to the semi-circular canals. The auditory nerve is attached to the cochlea and it sends the sounds to the brain.
How do you calculate the average speed?
Average speed = (Minutes x 60) / Distance
