physics Flashcards

14352682414	weight	force a body exerts due to the pull of gravity	0
14352682415	mass	the measure of the amount of material in a body	1
14352682416	momentum=	mass x velocity	2
14352682421	density is	mass per unit volume	3
14352682422	density=	mass/volume	4
14352682424	friction is	a force that opposes motion	5
14352682425	air resistance or drag	occurs when the object moves through air or fluid	6
14352682426	reduce friction by	lubrication	7
14352682427	friction acts in the	opposite direction of the motion of object	8
14352682433	1st law	a body will remain at rest or move at a constant velocity if the resultant force acting on the body is zero	9
14352682434	balanced forces exist when	two forces act in opposite directions but are the same size	10
14352682435	2nd law	if a resultant force acts on a body the body will not remain at rest or move at constant velocity, it will accelerate	11
14352682436	resultant force=	mass x acceleration	12
14352682438	distance is	the total amount of ground covered	13
14352682439	displacement is	shortest distance from start to finish in a certain direction	14
14352682440	speed is	rate of change of distance	15
14352682441	velocity is	rate of change in displacement	16
14352682442	acceleration is	rate of change in velocity	17
14352682443	scalar	has magnitude only	18
14352682444	vector	magnitude and direction	19
14352682445	acceleration=	velocity/time	20
14352682446	unit of acceleration	m/s²	21
14352682447	Work =	force x distance	22
14352682448	unit of work	newton meter	23
14352682451	centrepedal force depends on	mass of object speed of object radius of circle	24
14352682453	unit of momentum	kgm/s²	25
14352682454	change in momentum=	force x time	26
14352682455	momentum depends on	mass velocity	27
14352682457	conservation of momentum	when two bodies collide, the total momentum remains constant, providing that there are no external forces acting	28
14352682458	energy types	kinetic light sound EPE GPE chemical electrical nuclear magnetic heat	29
14352682466	GPE	the type of energy anything above the ground has	30
14352682468	nuclear	energy stored inside nucleus due to its missing mass	31
14352682469	unit of energy	joules	32
14352682472	formula for kinetic energy=	½mv²	33
14352682473	principle of energy	energy cannot be created or destroyed, only changed into different forms	34
14352682474	power	rate at which work is done or energy is transferred	35
14352682475	power=	work done/time	36
14352682497	JJ Thompson	plum pudding model a sphere of positive charge with tiny negative electrons stuck in it	37
14352682498	Rutherford	fired positively charged alpha particles at a thin gold foil most alpha particles went straight through with no or little deflection some were deflected through very large angles and a few came straight back introduced nucleus	38
14352682500	Bohr	introduced the idea of electrons orbiting a nucleus un discrete energy levels, by studying the emission spectra of gases	39
14352682502	alpha α ⁴ He ₂	helium nucleus positively charged deflected by magnetic field	40
14352682507	nuclear fission	This is when heavy nuclei can be forced to split into two lighter nuclei	41
14352682513	nuclear fussion	this is when two lighter nuclei combine to form a single heavier nucleus	42
14352682517	if light enters or leaves a different material, of different optical density	the speed of light changes and therefore the direction of travel changes	43
14352682518	light travels in	straight lines	44
14352682519	light speed in vacuum	300000km/s	45
14352682520	dispersion	spreading out of white light into its separate colours	46
14352682522	conditions of total internal refraction	light must be travelling from a more optically dense material to a less optically dense material angle of incidence is greater than the critical angle for the given material	47
14352682530	waves are produced	by vibrations	48
14352682531	waves	transfer energy from one point to another in the direction in which the wave is travelling, without the movement of material as a whole	49
14352682532	transverse waves	direction of travel of the wave is perpendicular to the direction of vibrations e.g. mexican wave	50
14352682533	longitudinal wave	direction of travel of the wave is parallel to the direction of vibration e.g. audible sound	51
14352682534	amplitude A	the maximum displacement from the equilibrium position	52
14352682535	period T	time taken for one complete vibration	53
14352682536	wavelength λ	distance between two neighbouring crest/troughs or compression/rarefactions	54
14352682537	frequency F	number of complete vibrations occurring in one second	55
14352682538	period=	1/frequency	56
14352682539	wave speed=	frequency x wavelength	57
14352682540	when waves are reflected the	speed frequency and wavelength fo not change	58
14352682541	when waves are refracted the	frequency does not change	59
14352682542	electromagnetic spectrum	group of waves that all have the same speed	60
14352682560	average velocity=	total displacement/total time	61
14352682561	net force=	mass x acceleration	62
14352682562	GPE=	mgh	63
14352682563	Electric Field lines point	away from positive charges	64
14352742867	Gravitation force is related to distance	inverse square	65
14352745200	Relationship between current and resistance	inverse	66
14352747454	Relationship between voltage and current	direct	67
14352749018	Relationship between mass and centripetal acceleration	none	68
14352750791	relationship. between speed and kinetic energy	exponential	69
14352753051	relationship between force and change in spring length	direct	70
14352754629	relationship between PEs and change in spring length	exponential	71