physics Flashcards
what do vectors have
vectors have magnitude and direction
vector quantities
force velocity displacement weight acceleration momentum
formula for distance travelled
average speed x time (s)
what do scalars have
scalars have magnitude but no direction
scalar quanataties
speed distance mass energy temp time
formula for acceleration
acceleration = final velocity - initial velocity div time
what is the formula for constant acceleration
final velocity squared - initial velocity squared = 2 x accel x distance
formula for resultant force
resultant force=mass x acceleration
newtons first law
if the resultant force on a stationary object is zero, the object will remain stationary. if the resultant force on a moving object is zero, it’ll just carry on moving at the same velocity..
in simple a resultant force is needed to make something start moving, speed up or slow down
formula for weight
mass x gravitational field strength
newtons third law
when two objects interact the forces they exert on each other are equal and opposite
formula for momentum
p=m x v momentum = mass x velocity
formula of force
change in momentum div time
all energy stores
kinetic, thermal, chemical, GPE, EP, electrostatic, magnetic and nuclear
formula for GPE
mass x grav feild strength x change in vertical height
formula of kinetic energy
0.5 x mass x speed squared
what is conservation of energy
energy can be stored, transferred and dissipated but never created or destroyed
all energy transfer with definition
mechanically- a force acting on a object e.g. pushing, stretching
electrically- a charge doing work against resistance e.g. charges moving around the circuit
by heating- energy transferred from a hotter object to a colder object
by radiation- energy transferred by waves
formula for efficiency (answer will be given as a decimal for percentage times by 100)
useful energy transferred by device divide total energy supplied to device
measuring waves practical in watere
1st using a signal generator attached to the dipper of the tank you can create water waves at a set frequency
2nd dim the lights then turn onj the strobe light you will seee a wave pattern made by shadows underneath
3rd change the frequency of the strobe light until the wave pattern ‘freezes’
4th the distance between each shadow line is equal to one wavelength then use wave speed = freq x wavelength
2 formulas for wave speed
v= distance over time v= freq x wavelength
refraction practical
1st place a transparent block on paper then trace around it and use ray box to shine light into it
2nd trace the incident ray and the emergent ray. remove the blovk and join up the two lines.
3rd draw the normal at the point where the ray entered the block. use protractor to measure the angle.
4th do the same on the other line
6th repeat this three times for accurate results
All em waves from highest freq to lowest freq
gamme rays, x-rays, uv, visible light, if, microwaves, radiowaves
How do we show efficacy
Diagrams
