Practice Test 2. a. 12 kn b. 17 kn c. 13 kn d. 5.0 kn e. 49 kn

Transcription

1 Prtie Test 2 1. A highwy urve hs rdius of 0.14 km nd is unnked. A r weighing 12 kn goes round the urve t speed of 24 m/s without slipping. Wht is the mgnitude of the horizontl fore of the rod on the r? d. 12 kn. 17 kn. 13 kn d. 5.0 kn e. 49 kn 2. A stunt pilot weighing 0.70 kn performs vertil irulr dive of rdius 0.80 km. At the ottom of the dive, the pilot hs speed of 0.20 km/s whih t tht instnt is not hnging. Wht fore does the plne exert on the pilot?. 3.6 kn up. 4.3 kn up. 2.9 kn down d. 2.9 kn up e. 5.8 kn down 3. A 0.50-kg mss tthed to the end of string swings in vertil irle (rdius = 2.0 m). When the mss is t the lowest point on the irle, the speed of the mss is 12 m/s. Wht is the mgnitude of the fore of the string on the mss t this position?. 31 N. 36 N. 41 N d. 46 N e. 23 N 4. A 0.20-kg ojet tthed to the end of string swings in vertil irle (rdius = 80 m). At the top of the irle the speed of the ojet is 4.5 m/s. Wht is the mgnitude of the tension in the string t this position?. 7.0 N. 2.0 N. 3.1 N d. 5.1 N e. 6.6 N

2 5. A 0.30-kg mss tthed to the end of string swings in vertil irle (R = 1.6 m), s shown. At n instnt when θ = 50, the tension in the string is 8.0 N. Wht is the mgnitude of the resultnt fore on the mss t this instnt? g tθ R v m. 5.6 N. 6.0 N. 6.5 N d. 5.1 N e. 2.2 N 6. A 0.40-kg mss tthed to the end of string swings in vertil irle hving rdius of 1.8 m. At n instnt when the string mkes n ngle of 40 degrees elow the horizontl, the speed of the mss is 5.0 m/s. Wht is the mgnitude of the tension in the string t this instnt?. 9.5 N. 3.0 N. 8.1 N d. 5.6 N e. 4.7 N 7. A re r trveling t 100 m/s enters n unnked turn of 400 m rdius. The oeffiient of (stti) frition etween the tires nd the trk is 1.1. The trk hs oth n inner nd n outer wll. Whih sttement is orret?. The re r will rsh into the outer wll.. The re r will rsh into the inner wll.. The r will sty in the enter of the trk. d. The r will sty in the enter of the trk if the driver speeds up. e. The r would sty in the enter of the trk if the rdius were redued to 200 m.

3 8. For plne to e le to fly lokwise in horizontl irle s seen from ove, in ddition to exerting fore downwrds on the ir. it must e inresing its speed.. it must exert fore on the ir tht is direted to the plne s left side.. it must exert fore on the ir tht is direted to the plne s right side. d. it does not need to exert fore: it must only move the wing flps out. e. it only needs to deflet the ir without exerting ny dditionl fore on the ir. 9. An ieot is trveling in irle on the ie. Hlfwy round the irle the sil nd the steering mehnism fll off the ot. Whih sttement is orret?. The ot will ontinue trveling in the irle euse there is no frition.. The ot will ontinue to trvel in the irle euse its veloity exerts fore on it.. The ot will move off on line tngent to the irle euse there is no fore on it. d. The ot will move off tngent to the irle euse there is fore on it perpendiulr to the ot direted to the outside of the irle. e. The ot will move off to the outside perpendiulr to the tngent line sine fore direted to the outside of the irle lwys ts on the ot. 10. A rok tthed to string swings in vertil irle. Whih free ody digrm ould orretly desrie the fore(s) on the rok when the string is in one possile horizontl position? N T T T N T W W W W () () () (d) (e)

4 11. The eqution elow is the solution to prolem. (2.00 kg)(8.00 m s )2 = 6.00 N (2.00 kg)(9.80 m 5.00 m s )(os180 ). 2 The est physil representtion of this eqution is. sphere of 2.00 kg mss under 6.00 N tension when t the ottom of vertil irle.. sphere of 2.00 kg mss under 6.00 N tension when t the side of vertil irle.. sphere of 2.00 kg mss under 6.00 N tension when t the top of vertil irle. d. sphere of 2.00 kg mss t ny point on horizontl irle. e kg geko running on the eiling with speed of 8.00 m/s. 12. The oeffiient of stti frition for the tires of re r is nd the oeffiient of kineti frition is The r is on level irulr trk of 50.0 m e rdius on plnet where g = 2.45 m s ompred to Erth s g = 9.80 m. If the r 2 2 s is to e le to trvel t the sme speed on the plnet s on Erth, the rdius of the trk on the plnet must e times s lrge s the rdius of the trk on Erth d e An irplne flies in horizontl irle of rdius 500 m t speed of 150 m/s. If the plne were to fly in the sme 1000 m irle t speed of 300 m/s, y wht ftor would its entripetl elertion hnge? d d e. 4.00

5 14. A single onservtive fore F x = (6.0x 12) N (x is in m) ts on prtile moving long the x xis. The potentil energy ssoited with this fore is ssigned vlue of +20 J t x = 0. Wht is the potentil energy t x = 3.0 m?. +11 J. +29 J J d. 9.0 J e. +20 J 15. A 0.40-kg prtile moves under the influene of single onservtive fore. At point A where the prtile hs speed of 10 m/s, the potentil energy ssoited with the onservtive fore is +40 J. As the prtile moves from A to B, the fore does +25 J of work on the prtile. Wht is the vlue of the potentil energy t point B?. +65 J. +15 J. +35 J d. +45 J e. 40 J 16. A 12-kg lok on horizontl fritionless surfe is tthed to light spring (fore onstnt = 0.80 kn/m). The lok is initilly t rest t its equilirium position when fore (mgnitude P = 80 N) ting prllel to the surfe is pplied to the lok, s shown. Wht is the speed of the lok when it is 13 m from its equilirium position? P m/s m/s m/s d m/s e m/s

6 16. A 0.60-kg ojet is suspended from the eiling t the end of 2.0-m string. When pulled to the side nd relesed, it hs speed of 4.0 m/s t the lowest point of its pth. Wht mximum ngle does the string mke with the vertil s the ojet swings up? d. 77 e A 2.0-kg mss swings t the end of light string (length = 3.0 m). Its speed t the lowest point on its irulr pth is 6.0 m/s. Wht is its kineti energy t n instnt when the string mkes n ngle of 50 with the vertil?. 21 J. 15 J. 28 J d. 36 J e. 23 J 19. A ertin pendulum onsists of 1.5-kg mss swinging t the end of string (length = 2.0 m). At the lowest point in the swing the tension in the string is equl to 20 N. To wht mximum height ove this lowest point will the mss rise during its osilltion? d. 77 m. 50 m. 63 m d. 36 m e. 95 m

7 20. A 0.04-kg ll is thrown from the top of 30-m tll uilding (point A) t n unknown ngle ove the horizontl. As shown in the figure, the ll ttins mximum height of 10 m ove the top of the uilding efore striking the ground t point B. If ir resistne is negligile, wht is the vlue of the kineti energy of the ll t B minus the kineti energy of the ll t A (K B K A )? A 10 mm 30 mm B. 12 J. 12 J. 20 J d. 20 J e. 32 J 21. A 2.0-kg mss is projeted from the edge of the top of 20-m tll uilding with veloity of 24 m/s t some unknown ngle ove the horizontl. Disregrd ir resistne nd ssume the ground is level. Wht is the kineti energy of the mss just efore it strikes the ground? kj kj kj d kj e kj

8 22. A skier weighing 0.80 kn omes down fritionless ski run tht is irulr (R = 30 m) t the ottom, s shown. If her speed is 12 m/s t point A, wht is her speed t the ottom of the hill (point B)? 40 A 30 m B. 17 m/s. 19 m/s. 18 m/s d. 20 m/s e. 12 m/s 23. A spring (k = 200 N/m) is suspended with its upper end supported from eiling. With the spring hnging in its equilirium onfigurtion, n ojet (mss = 2.0 kg) is tthed to the lower end nd relesed from rest. Wht is the speed of the ojet fter it hs fllen 4.0 m?. 90 m/s. 79 m/s. 96 m/s d. 83 m/s e. 57 m/s 24. A lok (mss = 4.0 kg) sliding on horizontl fritionless surfe is tthed to one end of horizontl spring (k = 100 N/m) whih hs its other end fixed. If the mximum distne the lok slides from the equilirium position is equl to 20 m, wht is the speed of the lok t n instnt when it is distne of 16 m from the equilirium position?. 71 m/s. 60 m/s. 80 m/s d. 87 m/s e. 57 m/s

9 25. A 20-kg mss is fstened to light spring (k = 380 N/m) tht psses over pulley s shown. The pulley is fritionless, nd the mss is relesed from rest when the spring is unstrethed. After the mss hs dropped 0.40 m, wht is its speed? k. 2.2 m/s. 2.5 m/s. 1.9 m/s d. 1.5 m/s e. 3.6 m/s 26. A spring (k = 600 N/m) is pled in vertil position with its lower end supported y horizontl surfe. A 2.0-kg lok tht is initilly 0.40 m ove the upper end of the spring is dropped from rest onto the spring. Wht is the kineti energy of the lok t the instnt it hs fllen 0.50 m (ompressing the spring 0.10 m)?. 5.3 J. 6.8 J. 6.3 J d. 5.8 J e. 6.5 J

10 27. A 1.5-kg lok sliding on rough horizontl surfe is tthed to one end of horizontl spring (k = 200 N/m) whih hs its other end fixed. If this system is displed 20 m horizontlly from the equilirium position nd relesed from rest, the lok first rehes the equilirium position with speed of 2.0 m/s. Wht is the oeffiient of kineti frition etween the lok nd the horizontl surfe on whih it slides? d e A 12-kg projetile is lunhed with n initil vertil speed of 20 m/s. It rises to mximum height of 18 m ove the lunh point. How muh work is done y the dissiptive (ir) resistive fore on the projetile during this sent? d kj kj kj d kj e kj 29. The lok shown is relesed from rest when the spring is strethed distne d. If k = 50 N/m, m = 0.50 kg, d = 10 m, nd the oeffiient of kineti frition etween the lok nd the horizontl surfe is equl to 0.25, determine the speed of the lok when it first psses through the position for whih the spring is unstrethed. k m. 92 m/s. 61 m/s. 71 m/s d. 82 m/s e. 53 m/s

11 30. In given displement of prtile, its kineti energy inreses y 25 J while its potentil energy dereses y 10 J. Determine the work of the nononservtive fores ting on the prtile during this displement.. 15 J. +35 J. +15 J d. 35 J e. +55 J