Physics Flashcards
Speed=
Distance/Time-m/s-v=d/t
Gradient of a line=
y step/x step=speed on a distance-time graph
On a distance-time graph what does a steep and shallow curve mean?
Steep-High Speed
Shallow-Low Speed
On a distance-time graph what does a constant gradient (not horizontal though) mean, and what does a horizontal line mean?
Constant gradient=constant speed
Horizontal Line=Speed is 0
What type of quantity is velocity and acceleration?
It is a vector quantity, it is equal to speed in a particular direction and has a size
Acceleration=
Change in Velocity/Time-m/s/s-a=triangle v/t
In Speed-Time graphs what is the area under the graph?
Distance Travelled
In Speed-Time graphs what is the gradient of the line equal to?
Acceleration
On a Speed-Time graph what does a flat/horizontal line mean?
Constant Speed
On a Speed-Time graph what does a straight/constant line mean?
Constant Acceleration
Weight=
mass x gravitational field strength-N/kg-w=mg
On Earth what is gravitational field strength?
10N/kg
Mass is measured in
kg
Density=
Mass(g)/Volume(cm3)-g/cm3-odd p=m/v
Moment of a force about a pivot=
Force x perpendicular distance from the pivot
What is Hooke’s Law?
F=kx
Applied Force=Force Constant for Object Under Test x extension of spring
Extension should be directly proportional to the applied force provided that the elastic limit is not exceeded
Force=
there are 5 answers
Mass x Acceleration Moment of a Force/Perpendicular Distance to Pivot Spring Constant x Extension Work Done/Distance Area x Pressure
Kinetic Energy=
1/2mass x velocity squared
Resultant force is the
net or overall force when size and direction of all the forces acting are taken into account
What is centripetal force?
The force which causes an object to move in a circle, usually acting at right angles to the direction the object is travelling at (like a swingball)
It acts towards the centre of a circle
The larger the mass (when it comes to centripetal force)
the larger the inertia (resists change in motion)
How do you increase centripetal force?
The mass of object increases
The speed of object increases
Radius of circle decreases
What is the significance of the limit of proportionality of an extension/load graph?
The point where the spring won’t go back into it’s original shape, so F doesn’t=kx anymore
What is meant by the centre of mass?
Where all the mass of an object can be considered to be concentrated
What circumstances are needed for an object to topple over?
The line of action of its weight is outside its base
Describe Brownian motion
The random movement of small particles in a gas or a liquid. The particles are constantly being hit rapidly by other moving particles
Pressure(Pa)=
Force/Area
Depth x density x gravitational field strength
Also to note Boyles Law= pV = constant
so p1V1=p2V2 Pressure x volume = constant
Describe a Mercury Barometer
A barometer half filled with mercury, and a vacuum above that, The bottom part is exposed to the air, and its pressure, so when it increases the volume of the vacuum drops, and the mercury rises. Measures atmospheric pressure
How do you show in an experiment that pressure increases with depth in liquids?
Make holes in a water bottle and fill it with water. The water spewing out of the top holes will not travel so far and so fast, but the pressured holes below will, for the weight of water above them will push down
How does a manometer work?
Measures pressure of a gas. U-Shaped glass piece with gas attached at one end and free to air at other. Half filled with liquid. The liquid on both sides will go up and down from being equal to each other when gas is attached
What is the equation for a manometer?
Atmospheric Pressure + Density of liquid x gravitational field strength x difference in height of 2 liquid surfaces
Pressure = atmospheric pressure +pgh
What is the difference between scalar and vector quantities?
Scalar-Size only
Vector-Size and Direction
Name the heat transformations in a Light Bulb Waterfall Bow and Arrow Battery/Cell
Light Bulb: Electric to heat and light
Waterfall: Gravitational potential to kinetic
Bow and Arrow: Strain to kinetic
Cell: Chemical to electrical
What are the three things can happen to energy?
Be transferred, be transformed or be stored
Describe gravitational potential energy and kinetic energy
GPE: The energy gained as an object is lifted away from the earth
KE: An energy an object has due to movement
Describe strain and chemical energy
Strain: The energy stored when an object changes shape
Chemical: Stored energy that can be released in chemical reactions
Describe internal energy, sound energy and electrical energy
Internal: The total kinetic and potential energies of all the particles in an object
Sound: Energy carried by a sound wave
Electrical: Energy carried by an electrical current
Describe thermal (heat) energy
The energy released when the temperature of a hot object decreases due to a decrease in its internal energy
Power (W)=
Electrical Power=
Energy/time
Current x Voltage
Angle of incidence (in reflection) is equal to…
…the angle of reflection
When light goes from a less dense material to a denser one, or slows down, it bends…
…towards the normal
When light goes from a denser material to a less dense one, or speeds up, it bends…
…away from the normal
Refractive Index, n=
Speed of Light in a Vacuum/Speed of Light in the Material
or
sin i / sin r
When does refraction turn to total internal reflection?
When the angle of incidence = the critical angle
When total internal reflection is taking place what is the angle of reflection?
The angle of incidence
In refraction what is the angle of refraction (equation)?
Sin(Angle of Incidence)/Refractive Index
Then that number Sin-1(
Which colours travel the fastest and slowest in glass?
Fastest-Red
Slowest-Violet
What is it called when light spreads out into the colours of the spectrum?
Dispersion
From lowest energy (longest wave length) to highest energy (shortest wave length) name the 7 things on the electromagnetic spectrum
Radio Microwave Infra-Red Visible Light Ultra-Violet X-Radiation Gamma
What type of waves are longitudinal and which ones are transverse?
Longitudinal-Sound Waves
Transverse-Light Waves