UNIT VII Central Force: Review Key

Size: px

Start display at page:

Download "UNIT VII Central Force: Review Key"

Pauline Davis
6 years ago
Views:

1 UNIT VII Centl oce: Review Key. Which of the following tteent e tue of n object oving in cicle t contnt peed? Include ll tht pply.. The object expeience foce which h coponent diected pllel to the diection of otion. A i fle; if the otion i in cicle t contnt peed, the net foce i pependicul to the diection of otion. b. Ineti cue object to ove in cicle. B i fle; it i centipetl foce which cue the cicul otion. Ineti (which i NOT foce) i eely the tendency of ny oving object to continue in it tightline, contnt peed pth. c. Thee cn be foce puhing outwd on the object long the net foce in inwd. C i tue; n object which ove in cicle ut hve net inwd foce. Thee e ny intnce of individul outwd foce which e exceeded by n individul inwd foce. d. Becue the peed i contnt, the cceletion i zeo. D i fle; cceletion occu when thee i chnge in velocity. Since the diection of the velocity vecto i chnging, thee i n cceletion - n inwd diected cceletion. e. The cceletion nd the net foce vecto e diected pependicul to ech othe. E i fle; the cceletion nd net foce e lwy diected in the e diection. In thi ce, nd e diected inwd; thi hppen to be pependicul to the tngentil velocity vecto. f. If the net foce cting upon the object i uddenly educed to zeo, then the object would uddenly dept fo it cicul pth nd tvel tngent to the cicle. i tue; if the net foce i 0 N, then the oving object will intin it tte of otion. At the intnt tht becoe 0 N, the object i oving tngent to the cicle. net g. The cceletion of the object i diected tngent to the cicle. G i fle; the cceletion i diected inwd; only the velocity i diected tngent to the cicle.

2 Unit VII Centl oce: Review pge. Ue the eult of the Centl oce Lb to tte the eltionhip between the following vible fo n object oving in cicle t contnt peed.. nd with contnt nd v. b. nd v with contnt nd. c. nd with contnt nd v. v d. If the of the object w tipled while the diu nd peed wee kept contnt, wht would hppen to the foce needed to keep the object oving in cicle t contnt peed? How do you know? Since the foce i popotionl to the with contnt diu nd peed (), tipling the would tiple the foce. 3v v new 3 3 old e. If the diu of the cicle the object w oving in w cut in hlf while the nd peed wee kept contnt, wht would hppen to the foce needed to keep the object oving in cicle t contnt peed? How do you know? Since the foce i inveely popotionl to the diu with contnt nd peed (c), cutting the diu in hlf would double the foce. v v new old f. If the peed of the object otion w doubled while the nd diu wee kept contnt, wht would hppen to the foce needed to keep the object oving in cicle t contnt peed? How do you know? Since the foce i popotionl to the que of the peed with contnt diu nd (b), doubling the peed would quduple the foce. v v new 4 4 old g. If the peed of the object otion w doubled, the of the object w cut in hlf, nd the diu w doubled, wht would hppen to the foce needed to keep the object oving in cicle t contnt peed? How do you know? A hown below, thee would be no chnge in the foce equied. v v new old

3 Unit VII Centl oce: Review pge 3 3. Which of the following tteent e tue bout gvittionl foce? Identify ll tht pply.. The gvittionl foce only ct between vey, vey ive object. A i fle; gvittionl foce e univel (Newton' big ide); they ct between ny two object which hve. b. The gvittionl foce between n object nd the Eth i inveely elted to the que of the ditnce between the object' nd the eth' cente. B i tue; if the ditnce i inceed, then the foce i deceed. c. The gvittionl foce cn ALWAYS be ccutely clculted by ultiplying the object by the gvittionl field tength ( g whee g 9. 8 N ). kg C i fle; It i not tue to y tht the gvittionl foce i ALWAYS equl to 9.8. The vlue of g vie with loction nd o t ditnce ignificntly futhe fo the eth' ufce, g i educed nd the gvittionl foce ut be coputed uing diffeent vlue of g. d. The gvittionl foce cting upon n object i the e the weight of the object. D i tue; weight nd gvittionl foce e ynonyou. e. The gvittionl foce between two object i independent of the of the lle of the two object. E i fle; gvittionl foce i popotionl to the poduct of the two e. Both e e ipotnt in the coputtion. f. If object A gvittionlly ttct object B with foce of X Newton, then object B will lo gvittionlly ttct object A with the e foce of X Newton. i tue; fo evey ction thee i n equl nd oppoite ection. Thi i Newton' thid lw, n inecpble elity bout foce. g. The doubling of the eption ditnce (eued fo the cente) between two object will hlve the gvittionl foce between the object. G i fle; doubling the eption ditnce will ke the foce one-fouth the ize.

4 Unit VII Centl oce: Review pge 4 h. It n object i plced two Eth-dii bove the ufce of the Eth, then the foce of gvittionl ttction between the object nd the Eth will be onefouth the gnitude on Eth' ufce. H i fle; plcing the object t two Eth-dii bove Eth' ufce will put it 3 Eth dii fo Eth' cente. Thi i equivlent to inceing the eption ditnce by fcto of 3; thi decee the foce by fcto of 9. i. Obiting tonut do not expeience foce of gvity; thi explin why they feel weightle. I i fle; obiting tonut ut be expeiencing the foce of gvity. Without thi foce, thee would be no centipetl foce nd no obit. 4. Which of the following tteent e tue bout the cceletion of gvity nd the gvittionl field tength? Identify ll tht pply.. The cceletion of gvity expeienced by object locted ne to (nd f fo) fo the Eth depend upon the of the object. GM A i fle; check out the eqution g. The vlue of doe not depend upon g the object'. b. The cceletion of gvity expeienced by object locted ne to (nd f fo) fo the Eth depend upon the of the Eth. B i tue; check out the eqution gin. The cceletion of gvity ceted by the eth depend upon the eth'. c. The cceletion of gvity expeienced by object locted ne to (nd f fo) the Eth i inveely elted to the que of the ditnce between the cente of the object nd the cente of the Eth. C i tue; check out the eqution one oe tie. The eption ditnce i locted in the denointo of the eqution, indicting n invee eltionhip. d. Inceing the of n object will incee the cceletion of gvity expeienced by the object. D i fle; like tteent A, thi tteent ke cli tht the cceletion of gvity depend upon the of the object. It doe not. In the deivtion of g fo the Univel Gvittion eqution, the of the object cncel.

5 Unit VII Centl oce: Review pge 5 e. Doubling the ditnce between n object nd the Eth' cente will decee the cceletion of gvity by fcto of fou. E i tue; g i inveely popotionl to the que of the ditnce; doubling of the ditnce en tht you ut divide the foce of gvity vlue by 4 ( ) to obtin the new foce of gvity vlue. f. The cceletion of n obiting tellite i equl to the cceletion of gvity t tht pticul loction. i tue; the cceletion of gvity i the cceletion which i cued by gvity when it i the only foce. o n obiting tellite, gvity i the only foce. g. If the of the Eth wee doubled (without n ltetion in it diu), then the cceletion of gvity on it ufce would be ppoxitely 0. G i tue; ccoding to the eqution, the vlue i diectly popotionl to the of g the Eth. An incee in of the Eth eult in popotionl incee in. g h. If the of the Eth wee doubled nd the diu of the eth wee doubled, then the two chnge would offet ech othe nd the cceletion of gvity on it ufce would till be ppoxitely 0. H i fle; g i ppoxitely 0 on Eth' ufce. Doubling the of the Eth would incee g to ppoxitely 0. Then doubling the ditnce fo the ufce of the eth to it cente would decee by fcto of 4. The new cceletion of gvity vlue would be ppoxitely 5 thee two ltetion do not offet ech othe. g. Clely, M G R M G g 0 E E 5 4 R E E 5. Which of the following tteent e tue bout tellite? Identify ll tht pply.. Stellite e flling pojectile. A i tue (otly); tellite e pojectile which e flling towd the Eth without flling into the Eth. They e flling in the ene tht (like ny pojectile) they e dopping below thei tngentil diection of otion.

6 Unit VII Centl oce: Review pge 6 b. All tellite follow cicul pth. B i fle; oe tellite tvel in ellipticl nd even vey ellipticl obit. o intnce, the plnet obit the un in ildly ellipticl pth. c. The obitl velocity equied of tellite i dependent upon the of the tellite; oe ive tellite would equie gete obitl peed. GM C i fle; the eqution fo the obitl velocity of tellite i v. The M i the of the centl body - the body being obited by the tellite. A een in the eqution, the obitl velocity i independent of the of the tellite. d. The obitl velocity of tellite doe not depend upon the of the plnet ound which it obit. GM D i fle; the eqution fo the obitl velocity of tellite i v. The M i the of the centl body - the body being obited by the tellite. Clely the obitl velocity depend upon the of the plnet being obited. e. A high-ltitude tellite will equie gete obitl peed thn lowltitude tellite. GM E i fle the eqution fo the obitl velocity of tellite i v. The in the denointo inide the dicl i the diu of the obit. Highe ltitude tellite hve gete diu of obit. Hence, the in the denointo incee, the equied obitl velocity will decee. f. By definition, geoynchonou tellite obit the eth in pefect cicle, intining the e ditnce bove the ufce of the Eth it ove ound the Eth. i fle; by definition, geoynchonou tellite h ynchonized o tched it obitl peiod to the ottionl peiod of the Eth bout it xi - 4 hou. Hence, it lwy ty bove the e point of the Eth. g. Stellite tvel fte long thei obitl pth when they e cloet to the Eth. G i tue; thi i n ide known ince Keple tht i explined by Newton' gvittionl lw. A tellite obit in n ellipticl pth, the foce of gvittion i getet t the tie when it i cloet to the Eth; thi foce cue gete cceletion nd peed of the tellite long thee neet loction of it obit.

7 Unit VII Centl oce: Review pge 7 h. The cceletion of tellite vie inveely with the que of it ditnce fo the cente of the Eth. Moe ditnt tellite hve lle cceletion. GM H i tue; the cceletion of tellite i given by the eqution g whee i the diu of the obit. The lge the vlue, the lle the cceletion. Thi i n invee que eltionhip. 6. Which of the following tteent e tue bout the otion of plnet bout the un? Identify ll tht pply.. The foce of gvity i the only foce which ct upon the plnet. A i tue; gvity i the only foce cting upon plnet. Think bout it - wht othe phyicl puh o pull cn you identify cting upon the Eth. (People puhing on it nd pulling it don't count.) b. Thei tjectoie e highly ellipticl. B i fle; thei tjectoie e indeed ellipticl. Yet in ot ce, the ellipe e vey cloe to cicle ince the eccenticitie e vey cloe to 0. c. The plnet which e futhet fo the un hve the getet peiod. 3 C i tue; thi i in ccod with Keple' thid lw: T. Expeing thi eqution 3 nothe wy depict the diect eltionhip between T nd : 3 T contnt. d. o ny given plnet, the peed i getet when the plnet i cloet to the un. D i tue; thi i Keple' econd lw of plnety otion. In ode to weep out equl e in equl tie, tellite ut be oving fte when cloet to the eth. e. The velocity vecto i diected tngent to the ellipticl pth. E i tue; t ll tie duing the obitl pth, the velocity of the plnet i tngent to the pth. Since the pth h lightly ellipticl ntue to it, the foce nd cceletion vecto e not neceily pependicul to thi velocity vecto. The pependicul oienttion of the nd vecto eltive to the v vecto i unique to cicul otion. f. To keep the plnet fo ecping the un' gvittionl field, the net foce vecto i getet when the plnet i futhet fo the un. i fle; the net foce i gvittionl foce. Gvittionl foce vy inveely with the que of the ditnce. Thu, plnet will expeience le foce when futhet fo the un.

8 Unit VII Centl oce: Review pge 8 7. In the dig t the ight, dw vecto ow which indicte the following fo n object which i oving in clockwie cicle. the net foce t point A. the cceletion t point B. the velocity t point C. 8. The dig t the ight how tellite obiting the Eth in n ellipticl pth in clockwie diection.. Dw vecto epeenting the velocity of the object t poition A. b. Dw vecto epeenting the foce on the object t poition D. c. Dw vecto epeenting the cceletion of the object t poition C. d. At which of the fou poition i the tellite oving ftet? See dig fo nwe. The foce nd cceletion vecto e diected towd the plnet being obited (which i t focu of the ellipe) nd the velocity vecto i diected tngent to the pth. The tellite ove ftet t C ince it i cloet to the plnet t tht point. 9. Two object ttct ech othe with foce of gvity of 36 N. If the ditnce epting the object i doubled, wht i the new foce of gvittionl ttction? G G N 9 N 4 0. Two object ttct ech othe with foce of gvity of 36 N. If the ditnce epting the object i doubled nd the e one of the object i tipled, then wht i the new foce of gvittionl ttction? 3 G 3 G N 7 N 4. Two object ttct ech othe with foce of gvity of 36 N. If the ditnce epting the object i inceed by fcto of 4 nd the e of both object e tipled, then wht i the new foce of gvittionl ttction? 3 3 G G N 0. N 6

9 Unit VII Centl oce: Review pge 9. Suppoe tht the cceletion of gvity on the ufce of plnet X i. Deteine the cceletion of gvity t loction. of dii fo the cente of plnet X. G 3. M M 0 G b. of 4 dii fo the cente of plnet X. G 0. M M 75 G c. of dii fo the ufce of plnet X. A ditnce of dii fo the ufce i equivlent to 3 dii fo the cente of the plnet. M M. 3 G G d. on the ufce of plnet X if the plnet wee twice lge (e diu). M G M G 4 e. on the ufce of plnet X if the plnet wee one-hlf lge (e diu). G M M 6. G 0 3. Suppoe tht plnet w locted.0 tie futhe fo the un thn the Eth' ditnce fo the un. Deteine the peiod of the plnet in Eth ye.

10 Unit VII Centl oce: Review pge 0 Thi quetion exploe the peiod diu eltionhip. A uch, Keple' Thid Lw - 3 tht the T fo ll the plnet obiting the un ut be utilized. T p e 3 e T T R R e 3 e T R T p T p p p.0r 3 E 3.0 T e.0 3 ye T p 4.6 ye 4. The cceletion of gvity on the oon i ppoxitely one-ixth the vlue on Eth' ufce. If peon weigh 60.0 N on the oon' ufce, wht i hi/he ppoxite on Eth? ), then. The of 60.0 N peon on the oon cn then be found: g 9.8 If the vlue on the oon i /6 th of the vlue on the Eth ( g g oon.63 g oon g oon g oon g oon N kg Since i unffected by loction (oon o eth o fee pce), the of the peon on eth i the e the on the oon kg. 5. Deteine the foce of gvittionl ttction between 5.0 kg othe nd 3.0 kg child if thei eption ditnce i 0.50 ete. 8 g 4.60 N 6. Ue the following infotion to deteine the obitl velocity t teetop level on the ufce of the oon.

11 Unit VII Centl oce: Review pge v 680 o M of oon = Rdiu of oon =.740 kg 6 o Quetion 7 0, identify the type of foce which cue the following boldfced object to tvel long cicul pth. 7. An ee i tied to ting wung in hoizontl cicle.. gvity b. nol c. tenion d. pplied e. fiction f. ping g. electicl h. gnetic C - Tenion (A ting i ttched to the ee nd pull it towd the cente point of the cicle.) 8. The oon obit the eth.. gvity b. nol c. tenion d. pplied e. fiction f. ping g. electicl h. gnetic A - Gvity (All e ttct with foce of gvity. In the ce of the oon nd the eth, gvity pull on the oon in diection which i oughly pependicul to it pth.) 9. A c ke hp ight-hnd tun long level odwy.. gvity b. nol c. tenion d. pplied e. fiction f. ping g. electicl h. gnetic E - iction (Once the wheel e tuned, fiction cn puh pependicul to the wheel' diection, puhing the c towd the cente of the cicle.) 0. A olle cote c pe though loop. Conide the c t the botto of the loop.. gvity b. nol c. tenion d. pplied e. fiction f. ping g. electicl h. gnetic B - Nol (Thee e two foce t the botto of the loop; gvity pull outwd fo the cente; but the nol foce exceed the gnitude of gvity, puhing inwd with ufficient foce to upply the needed centipetl foce.). Dn i pcticing diving in cicle in the ll pking lot. Hi c i oving long cicle of diu 6.0 nd the coefficient of ttic fiction between the tie nd the

12 Unit VII Centl oce: Review pge pking lot i Wht i the ftet peed Dn could be diving without hi c lipping? Begin by dwing foce dig of Dn c. v 0. g f N f net v. An 80. kg peon dive ove hill with diu of cuvtue of 30.. At wht contnt peed would the dive hve to be tveling in ode to feel weightle he dive ove the hill? Dw foce dig of the dive to epeent the itution. v 7 g net g v 3. You pin 0. 0 kg ee tied to the end of 0.60 long ting in flt, hoizontl cicle nd t contnt peed. The peiod of the ee i Wht i the contnt peed of the b. Wht tenion exit in the ting? ee? v 5 T T 0N

13 Unit VII Centl oce: Review pge 3 c. Wht peed would the ee hve if the tenion w thee tie the tenion in (b)? v 44 becue to get the net foce to be thee tie gete the peed would hve to incee by que oot of An 80. kg peon dive though cicul vlley with diu of cuvtue of 0. t contnt 0... Dw quntittive foce dig of the dive t the poition hown. Doe he feel hevie, lighte, o nol he dive though the vlley? How do you know? (Pove you nwe by clculting the Nol oce nd coping it to the Weight of the dive.) N g o net N g N 400N He feel hevie! He feel oe thn 3 tie hi weight. b. At wht contnt peed would the 80. kg dive hve to be tveling in ode to feel thee tie hi nol body weight he dive though the vlley? Begin by dwing foce dig of the dive fo thi itution. v 0. I did not how ll of the wok necey fo the witten ection becue it w too tie conuing to type it ll. Check the in-cl nwe key fo ll tep. And eebe tht you e equied to how ll of you wok on the tet.

Satellite Orbits. Orbital Mechanics. Circular Satellite Orbits

Satellite Orbits. Orbital Mechanics. Circular Satellite Orbits Obitl Mechnic tellite Obit Let u tt by king the quetion, Wht keep tellite in n obit ound eth?. Why doen t tellite go diectly towd th, nd why doen t it ecpe th? The nwe i tht thee e two min foce tht ct