Study Guide Physics Pre-Comp 2013

Transcription

1 I. Scientific Measurement Metric Units S.I. English Length Meter (m) Feet (ft.) Mass Kilgram (kg) Pund (lb.) Weight Newtn (N) Ounce (z.) r pund (lb.) Time Secnds (s) Secnds (s) Vlume Liter (L) Galln (gal) Temperature Kelvin (K) r Celcius ( ) Fahrenheit ( ) Metric Prefixes Name Abbreviatins Number Assciatin Name Abbreviatins Number Assciatin Pic p Tera T Nan n Giga G Micr Mega M Mili m Kil k Centi c Hect h Deci d Deka Da Cnvert between metric units (including with prefixes) II. Psitin, Velcity, and Acceleratin Definitins related t mtin Reference pint: A crdinate system used t define a mtin. Psitin: Where an bject is precisely lcated. Mtin: Mvement relative t a fixed pint. Speed: The measure f hw fast smething is mving. Vectr quantity. Velcity: Speed with directin. Vectr quantity. Acceleratin: Rate f change f velcity. Equatin fr speed and units Equatin: speed equals distance divided by time Units: meters per secnd (m/s) Average speed frmulas with distance and time Difference between instantaneus and average velcity Instantaneus Velcity: The velcity that smething is traveling at any ne instance. Average Velcity: Ttal displacement ver a time interval. If the bject is traveling with cnstant velcity its instantaneus and average velcities will be the same. Difference between psitive and negative acceleratin Psitive acceleratin is acceleratin in the directin f velcity. Negative acceleratin is acceleratin ppsite the directin f velcity. 1 Made By Ashley Thmas

2 Graphing psitin vs. time and relatin t velcity and acceleratin See Attachment 1 Graphing psitin vs. time and hw this illustrates acceleratin See Attachment 1 Equatin fr acceleratin Units: m/ Instantaneus velcity given initial velcity, acceleratin, and time Differentiate between speed and velcity Speed: Distance f an bject ver time Velcity: change in speed with directin. Calculate resultant velcity (parallel vectrs nly ) Calculate acceleratin Slve fr any variable in the V final equatin III. Frces and Newtn s 1 st and 2 nd laws f mtin Newtn s first law f mtin An bject at rest will stay at rest, and an bject in mtin will stay in mtin at a cnstant velcity, unless acted upn by an unbalanced frce. Inertia: The tendency f an bject t resist changes in its velcity, whether in mtin r mtinless. Mass is the measure f inertia in respnse t an effrt made t stp it, start it, ect. Mass and weight Definitin f mass as inertia: The prprtinal frce t cause a unit f acceleratin. Mass (as a quantity f matter: Quantity f matter in an bject. The amunt f stuff in an bject. Weight: The magnitude f the frce f gravity acting n an bject. Mass is the amunt f stuff but weight is the amunt f stuff with the frce f gravity acting n it. Newtn s secnd law f mtin The acceleratin f an bject is directly prprtinal t the net frce acting n the bject, is in the directin f the net frce, and is inversely prprtinal t the mass f the bject. Simplified Versin f 2 nd law: Net frce is equal t the mass times the acceleratin. F=ma Frce Frce: Any influence that tends t accelerate an bject. Mre simply any kind f push r pull. Net Frce: The cmbinatin f all the frces that act n an bject. Units: Newtn 2 Made By Ashley Thmas

3 Equilibrium Equilibrium: A state f balance. Static Equilibrium: When all the frces acting n an bject are balanced and the bject is nt mving. Dynamic Equilibrium: When all the frces acting n an bject are balanced and the bject is mving. Static and dynamic equilibrium bth invlve bjects in a state f equilibrium but in dynamic the bject is in mtin, but mving with a cnstant velcity. Balanced vs. unbalanced frces Balanced Frce: Equilibrium, the sum f frces is equal t zer. Unbalanced Frce: Nt in equilibrium, the sum f frces is equal t acceleratin times mass. Definitin f nrmal frce Nrmal Frce: A frce perpendicular t the surface, 90 degrees. Frictinal frce Frictin Frce: A frce ppsite t mtin, and parallel t the grund that it is traveling n. Causes: FRICTION!!!! Hke s law Distance f stretch r squeeze (expansin r cmpressin) f an elastic material is directly prprtinal t the applied frce. Calculate weight given mass and acceleratin due t gravity (W=mg) Slve fr any variable in the F=ma equatin Calculate net frce using Newtn s secnd law f mtin. Calculate net frce given parallel frces, including applied frce and tensin. Calculate, Hke s law, using the frmula and slve fr any variable. IV. Newtn s 3 rd law f mtin Newtn s third law f mtin Fr every actin there is an equal and ppsite reactin Understand the actin and reactin relatinship. V. Mmentum Mmentum Mmentum: inertia in mtin. The prduct f the mass and the velcity f an bject. Has magnitude and directin and therefre is a vectr quantity. p=mv The relatinship between inertia and mmentum is mmentum is inertia but in mtin. Impulse: dn t have t knw fr cmmn sectin f pre-cmp, Impulse: the prduct f frce and the time interval during which the frce acts. Prduces change in mmentum. j= j=ft Be able t slve fr any variable. Definitin f cnserved quantity 3 Made By Ashley Thmas

4 Cnserved: Term applied t a physical quantity, such as mmentum, energy, r electric charge, which remains unchanged during interactins. Cnservatin f mmentum: In the absence f a net external frce, the mmentum f an bject r system f bjects is unchanged. Analyze mre advanced situatins invlving impulse and mmentum See knw hw t Slve fr any variable in the mmentum equatin Slve prblems f cllisins using the cnservatin f mmentum Calculate final velcity after a cllisin between tw bjects that stick Use Newtn s secnd law, mmentum, acceleratin, and time t slve fr any variable using tw equatins. VI. Energy Wrk Wrk: The prduct f the frce n an bject and the distance thrugh which the bject is mved (when frce is cnstant and mtin is in a straight line in the directin f frce) Wrk is dne when a frce prduces mtin. W=Fd Units: Jule (J) Energy Energy: Anything that can change the cnditin f matter. Cmmnly defined circularly as the ability t d wrk; Units: Jule (J) Mechanical energy There are tw types f mechanical energy, which are ptential and kinetic. Ptential Energy: Energy f psitin, usually related t the relative psitin f tw things, such as a stne and the earth (gravitatinal ptential energy), r an electrn and a nucleus (electric PE). Raised psitin (gravitatinal) r a cnditin (e.g. cmpressed springs, rubber bands, Elastic PE) Gravitatinal Ptential Energy: The ptential energy f a bdy due t elevated psitins. Kinetic Energy: Energy due t mtin. Energy strage: Spring Energy: Energy due t a spring. Energy calculatins 4 Made By Ashley Thmas

5 Law f cnservatin f energy Energy can t be created r destryed. Only true if nly cnservative frces (e.g. gravitatinal energy, spring frces, electric frces) act n the bjects, n nn-cnservative frces (e.g. Frictin, applied, and tensinal frces). Wrk-energy therem (wrk- kinetic energy therem) Speed will increase if the wrk is psitive Speed will decrease if the wrk is negative Slve fr any variable in the wrk frmula Slve fr any variable in the frmulas frm the energy calculatin sectin Calculate the ttal energy f a simple system f a mving bject r spring system at a given height. VII. Other Frmulas: Attachment 2 VIII. GOOD LUCK!!! 5 Made By Ashley Thmas