Year 9 (Motion, energy, effeciency, waves, color, ect.) Flashcards
what is weight?
weight is a force that acts towards the centre of the earth.
what is energy?
something needed for something to change or work
what unit is used to mesure energy?
Joule (J) calorie (cal)
what types of energy?
chemical,kinetic,thermal,strain,elastic potential,Gravitational potential,atomic,nuclear
what is the law of conservation of energy?
energy cannot be created or destroyed. It can only be transferred form one store to store
what is a vector
a quantity that has both a size and a direction.
Examples of vectors
Any force, velocity, displacement, momentum, and acceloration
what is scalar
a quantity that has magnitude but not a direction
what is magnitude
size
examples of scalars
mass,distance,speed
what is velocity
the speed of an object in a particular direction.
what is acceleration.
a mesure of how quickly the velocity of something is changing.
acceleration ==
(delta)speed / time
speed and velocity ==
dist/time
what is displacement
distance in a straight line ( has a direction)
WHat is newtons first law of motion?
a moving object will continue to move at the same speed unless an external force acts on it.
a stationary object will remain at rest ubnless an external force acts upon it.
WHat is weight?
weight is a force that acts towards the centre of the earth
WHat are all forces mesured in?
Newtons
What are vector quantities?
quantities that have both magnitude and direction
What is magnitude?
Size
What is Mass?
mass mesures the amount of matter in something and doesnt have a direction.
What are scalar quantities?
quantities that have size but not direction
What are examples of vectors ?
Forces, velocity, displacement, momentum and acceloration
what are examples of scalars?
distance, speed,mass,energy
What is displacement?
the distance covered in a straight line
What is speed?
A mesure of disance an object travels in a given time.
What is the velocity/speed equation?
dist/time
WHat is the acceleration equation?
delta speed/ time
what is an independant variabke?
the thing you change
What is the dependdent variable
the thing you mesure
what is the control variable?
somethingyou keep the same
what are quantities?
things we can mesure
what is energy
the capacity to do something it cant be created or destroyed, only transfered from one source to anotther
What are forms of energy called?
STores
what are some types of energy
elastic potential, nuclear thermal, kinetic, vibrational,chemical, gravitational potention
what is efficiency?
Efficiency is a measure of how good a machine/process is at transferring energy into useful forms.
whats the equation for efficiency?
usefulenergy/totalenergy
What do waves do?
they transfer energy/ information without transferring matter!
WHat is the amplitude?
the distance between the middle line and a crest
the maximum displacement of a wave particle from equilibrium [metres]
What is wavlenth
the distance from crest to crest
the distance between one crest/trough to the next crest/trough
Transverse
the oscillations are perpendicular to the wave’s direction of travel
Longitudal
the oscillations are parallel to the wave’s direction of travel
Frequency in waves
how many waves pass every second [Hertz
Speed in waves
how fast a wave travels [metres per second]
Speed of a wave equation
v = f x λ
What is ultra sound?
sound over 20khs (humans cant hear)
WHat is darkness?
the absence of light
Why do we have colors?
Certain colours can be seen because different materials reflect certain frequencies of light.
Diffuse reflection
Materials with rough surfaces reflect light in all directions. We call this…
Specular relection
Highly polished materials, like mirrors, or my car, reflect light evenly. This is known as…
Diffusion
Spreading out of ( High concentration - Low)
Visible spectrum
The range of colors/ light we can see
How does color reflection work?
If soething is a certain color, it absorbs all other frequencies of light then that color. It reflects the color is appears as, that how we can see it.
