Physics Defintions Flashcards
Static Friction
force opposes tendency motion stationary object rel to surface
Kinetic Friction
force opposes tendency motion moving object rel to surface
Inertia
Property resist change in state of rest or const vel
Newtons 1
const vel/rest remains until fnet>0
Newtons 2
When fnet acts, obj a in direc of fnet. A direc prop fnet inverse prop mass
Newtons 3
Obj A exerts force on obj B, obj B exerts = mag opp direc on obj A
Grav
Every body attract every other body force direc prop product masses inverse prop square distance between
Coloumbs
Electrostatic f of attrac/repulse exerted by one charge on another obj direc prop product charges inverse prop square distance between
Isolated system
a system where resultant external force is zero.
Electric Field
Region in space where electrostatic charge experiences a force
Electric Field Strength/At a point
electrostatic force experienced per unit positive charge placed at that point
Ohms Law
Current along a conductor direc prop to potential difference along the conductor provided temp constant
Power
Rate at which work is done
Resistance
Ratio of potential difference across a resistor to current in the resistor
Potential Difference
Energy transferred per unit charge flowing between 2 points through a conductor
Emf
Energy provided by battery per unit charge flowing through the battery
Internal Resistance
Resistance within a battery when current is flowing which causes a decrease in potential difference that the battery can supply to the external circuit
Momentum
Product of m and v
Newtons 2 in terms of momentum
The resultant/net force acting on an object is equal to the rate of change of momentum of the object in the direction of the resultant/net force.
Impulse
product of the resultant/net force acting on an object and the time the resultant/net force acts on the object
Elastic Collision
A collision in which total momentum and kinetic energy are conserved
Projectile
obj given vi after which fg only force on it
Free fall
obj only under fg
Work energy theorem
Net work done = delta EK
Conservative force
A force where work done indep path taken (Fg)
Conservation emech
Emech in isolated system remains constant
Doppler
Apparent change in frequency of sound detected by listener as result of rel motion between source of sound and listener
Use of doppler
Doppler Flow Meter - med field for rate of blood flow
Doppler Foetal Monitor - US
Doppler Radar Gun - Speed of moving vehicle
Red Shift
When star moves away from earth light waves behind star become spread out ie wavelength inc freq dec. Light shifts towards the red end of spectrum
Blue Shift
When start moves toward earth light waves ahead of star become compressed ie wavelength dec freq inc. Light towards blue end of spectrum
Why universe expand?
Light from most galaxies observed is redshifted implying expansion
