Sat力學(xué)運(yùn)動(dòng)學(xué)

1、Sat力學(xué)運(yùn)動(dòng)學(xué) 1. An object that smoving with constant speed travels once around a circular path.True statements about this moti on in clude which of the follow ing? A. The displaceme nt is zeroB. The average speed is zero C. The accelerati on is zeroD. None of the above A 2. Which of the followi ng must

2、always be true? 1f an object acceleration is constant,then it must move in a straight line 2f an object acceleration is zero,then its speed must remain constant 3f an object speed remains constant,then its acceleration must be zero. A. 1 and 2 only B. 1 and 3 only C. 2 on ly D. 3 on ly E. 2 and 3 on

3、ly C 3. A baseball is thrown straight upward.What is the ball acceleration at its highest point? A. 0 B. (1/2)g,dow nward C. g, down ward D. (1/2)g, upward E. g,upward C 4. How long would it take a car,start ing from rest and accelerati ng un iformly in a straight line at 2 5m/s ,to cover a distanee

4、 of 200m? A. 9s B 10.5s C. 12.0S D. 15.5S E. 20.0S A 5. A rock is dropped off a cliff and strikes the ground with an impact velocity of 30m/s.How high was the cliff? A. 15m B. 20m C. 30m D. 45m E. 60m D 6. A soccer ball at rest on the gro un d,is kicked with an in itial velocity of 10m/s at a launch

5、 an gle of 300 .Calculate its total flight time , assu ming that air resista nee is n egligible. A. 0.5s B. 1s C. 1.7s D. 2s E. 4s B 7. A sto ne is throw n horiz on tally with an in itial speed of 30m/s from a bridge. Find the stone total speed whe n it en ters the water 4 sec onds later(lg nore air

6、 resista nee.) A. 30m/s B. 40m/s C. 50m/s D. 60m/s E. 70m/s C 8. Whieh one of the following statements is true concerning the motion of an ideal projectile launched at an angle of 45 0 to the horizontal? A. The accelerati on vector points opposite to the velocity vector on the way up and in the same

7、 direct ion as the velocity vector on the way dow n B. The speed at the top of the trajectory is zero. C. The object total speed rema ins con sta nt duri ng the en tire flight D. The horiz on tal speed decreases on the way up and in creases on the way dow n E. The vertical speed decreases on the way

8、 up and in creases on the way dow n E 9. Which pair of forces can produce a resulta nt of 15 n ewt ons? A. 20N,20N B. 25N,5N C. 5N,5N D. 7N,7N E. 5N,3N A 10. As the an gle betwee n two con curre nt forces in creases,the magn itude of their resulta nt A. i ncreases only B. decreases and the n in crea

9、ses C. i ncreases and the n decreases D. rema ins the same E. decreases only E 11. A girl walks 2 meters north, 4 meters west,a nd 2 meters south.Her final displaceme nt is A. 4 m east B. 4m west C. 2m north D. 2m south E. 5m n orthwest B o 12. A cart is pulled by a rope mak ing an an gle of 45to th

10、e horiz on tal.lf 100 n ewt ons of force are applied to the rope,the magn itude of the horiz on tal comp onent force is approximately A. 45N B. 141N C. 100N D. 80N E. 71N E 13. The resulta nt of a 3-n ewt on and a 4-n ewt on force acting simulta neously on an object at right an gles to each other is

11、,i n n ewt ons A. O B. 1 C. 3.5 D. 5 E. 7 D 14. Two force act together on an object.The magn itude of their resulta nt is least whe n the an gle betwee n the forces is A. 0 B. 45 C. 60 D. 90 E. 180 E 15. The resulta nt of a 5-n ewt on and a 12-n ewt on force acti ng simulta neously on an object in t

12、he same directi on is,i n n ewt ons. A. 0 B. 5 C. 7 D. 13 E. 17 E 16. A vector is given by its components,A x =2.5 and A y =7.5.What angle does vector A make with the positive x-axis? 0 A. less than 45 0 B. equal to 45 0 0 C. more tha n 45but less tha n 45 D. 90 0 E. not eno ugh in formati on provid

13、ed C 17. Which of the following sets of displacements have equal resultants when performed in the orded give? 1.6m east,9 m n orth,12 m west 2.6m n orth,9 m west, 12 m east 3. 6 m east, 12 m west, 9 m n orth 4. 9 m n orth, 6 m east, 12 m west A. 1 and 4 B. 1 and 2 C. 1,3 an d4 D. 1,2,4 E. 2 and 4 C

14、18. The speeds of an object at the ends of 4 successive seconds are 20,25,30,and 35 meters per sec on d,respectively.The acceleratio n of this object is A. 5m/s B. 5m/s 2 C. 5s/m 2 D. 5s/m E. 20m/s B 19. A bomb is droppdd form an airpla ne movi ng horiz on tally with a speed of 200 kilometers per ho

15、ur. If the air resista nee is n egligible, the bomb will reach the ground in 5 sec onds whe n the altitude of the pla ne is approximately A. 50m B. 75m C. 125m D. 250m E. 300m C 20. While an arrow is being shot form a bow ,it is accelerated over a dista nee of 2 meters.At the end of this accelerati

16、on it leaves the bow with a speed of 200 meters per sec on d.The average accelerati on imparted to the arrow is 2 A. 200m/s 2 B. 400 m/s 2 C. 500 m/s D. 1000 m/s 2 E. 10000 m/s2 E 21. On an unknown pla net,a n astr on aut drops an object from rest.She observes thst the object falls a dista nee of 10

17、 meters duri ng a time in terval of 2 sec on ds.What is the magn itude of the accelerati on due to gravity on that pla net? A. 30m/s 2 2 B. 25 m/s 2 C. 15 m/s 2 D. 10 m/s E. 5 m/s2 E 21.A n object has an in itial velocity of 15 meters per sec ond . How long must it accelerate at a con sta nt rate of

18、 3 meters per scond squared before its average velocity is equal to twice its in itial velocity? A. 5s B. IOs C. 15s D. 20s E. 25s B 22. A handball is tossed vertically upward with a velocity of 19.6 meters per second . Approximately how high will it rise? A. 15m B. 20m C. 25m D. 30m E. 60m B 0 23.

19、A projectile is launched at an angle of 45 with a velocity of 250 meters per secondf air resista nee is n eglected, the magn itude of the horiz on tal velocity of the projectile at the time it reaches maximum altitude is equal to A. 0m/s B. 175m/s C. 200m/s D. 250m/s E. 300m/s B 24. A projectile is

20、laun ched horiz on tally with a velocity of 25 meters per sec ond form the top of a 75 meter cliff.How many sec onds will the projectile take to reach the bottom? A. 15.5 B. 9.75 C. 6.31 D. 4.27 E. 3.91 E 25. A projectile is launched from the ground with an initial velocity of 75m/s at an angle of 2

21、50 .Ignore air resistance .At its maximum height,the acceleration of the object is equal to A. 0 B. 0.5g C. 0.7g D. g E. 2g D 26. At a launch angle of 45 0 .,the range of a launched projectile is given by v i A. v 1 B. 2 g V C. - 2g D. .2g 2Vi E. - g A 27. A projectile is laun ched horiz on tally fr

22、om aflat roof of height h and with velocity v.If the height is kept constant and the velocity is doubled (ignoring air resistance),the time the projectile takes to reach the ground will A. double B. quadruple C. halve D. quarter E. remain the same E 28. For a projectile launched from the ground at a

23、90 angle (ignore resistance),the maximum height reached is give n by A. 2v 2 2 B. .2v i /2g 2 C. vi /g 2 D. vi g 2 E. 2 vi g B 29. A projectile is launched from the ground with a velocity of 300m/s at an angle of 300 .Ignoring air resista nee, the approximate time the projectile will take to reach i

24、ts maximum height is equal to A. 15 sec onds B. 20 sec onds C. 25 sec onds D. 30 sec onds E. 35 sec onds A 30. An object is mov ing around a circle of radius 1.5 meters at a con sta nt velocity of 7 meters per sec ond. The freque ncy of the moti on, in revoluti on per sec on d, is A. 0.24 B. 0.53 C.

25、 0.67 D. 0.74 E. 0.98 31. A n object un dergoes un iform accelerated moti on. If the radius of the path is 2 meters and the period is equal to 4 sec on ds, the magn itude of the cen tyipetal accelerati on is equal to A. 5m/s 2 B. 10 m/s 2 2 C. 20 m/s 2 D. 25 m/s 2 E. 30 m/s A 32. A n object un dergo

26、es uniform accelerated motio n. If the radius of the path is equal to 1.5 meters 2 and the magnitude of the centripetal acceleration is equal to 6 m/s ,the magnitude of the tangen tial velocity is equal to A. 3m/s B. 4 m/s C. 5 m/s D. 6 m/s E. 9 m/s A 33. What is the approximate weight of a 7.5-kilo

27、gram mass sitti ng on the surface of Earth? A. 7.5N B. 0.75N C. 75N D. 17.5N E. 27.5N C 34. A 15- kilogram mass is slidi ng along a frictionl ess floor with an accelerati on of 5 meters per sec ond squared.What is the magn itude of the net force act ing on the mass? A. 15N B. 20N C. 3N D. 75N E. 10N

28、 D 35. A 3- kilogram mass is traveli ng at 15 meters per sec ond whe n frictio n begi ns to decelerate it to a stop in 5 sec on ds. What is the magn itude of the force of friction? A. 9N B. 3N C. 45N D. 60N E. 15N A 36. A pers on is sta nding on a bathroom scale in an elevator and no tices that her

29、weight is less tha n no rmal. This means that the elevator: A. must be moving upward B. must be moving dow nward C. must be at rest D. must have positive accelerati on E. must have n egative accelerati on E 37. A mass is slidi ng dow n an in cli ne .As the an gle of elevati on for the in cli ne in c

30、reases, the magn itude of the comp onent of its weight perpe ndicular to the in cli ne: A. i ncreases B. decreases C. .i ncreases,the n .decreases D. decreases the n in creases E. rema ins the same B 38. A 4-kilogram mass is accelerated by a horiz on tal force of 15 n ewt on s,If the magn itude of t

31、he accelerati on is 3 meters per sec ond squared,how much fricti on is acti ng on the mass? A. 5N B. 15N C. 0N D. 27N E. 3N E 39. A 30kg mass is resti ng on a rough, horiz on tal surface. A horiz on tal force of 100N is required just to start it movi ng. What is the approximate value for the coeffic

32、ie nt of static frictio n? A. 0.5 B. 0.4 C. 0.3 D. 0.2 E. 0.1 C 40.If value of an object is tripled , its kin etic en ergy is A. 1/9 B. 1/3 C. 3 D. 6 E. 9 E 41. questio ns1-3 A pers on havi ng a mass of 60 kilograms exerts a horiz on tal force of 200 n ewt ons in push ing a 90-kilogram object a dist

33、a nee of 6 meters along a horiz on tai floor. He does this at con sta nt velocity in 3 sec onds (1) The weight of this pers on is, in n ewt ons, approximately A. 40 B. 90 C. 200 D. 400 E. 600 E (2) The work done by this pers on is, in joules, A. 540 B. 1080 C. 1200 D. 3600 E. 5400 C (3) The force of

34、 frictio n is A. exactly 60N B. between 60 and 90N C. exactly 90N D. exactly 200N E. greater than 200N D 42. question 1-2 The 1000-n ewt on weight of a pile driver falls freely from rest;it drops 25 meters, strikes a steel beam, and drives it 3 cen timeters into the gro und. (1) The kinetic energy o

35、f the weight of the pile driver just before it hits the beam is, in Newto n. meters, A. 3000 B. 25000 C. 75000 D. 200000 E. 800000 B (2) . The speed of the weight just before hitti ng the beam is,i n meters per sec ond, approximately A. 0.25 B. 3 C. 25 D. 22 E. 64 D 43. A spri ng with a force con st

36、a nt k=500N/m is stretched by a dista nee of 0.2 meter. How many joules of pote ntial en ergy are stored in the spri ng? A. 500j B. 250j C. IOj D. 5j E. O.4j C 44. Which of the follow ing is equivale nt to 1 joule? A. kg.m/s 2 B. kg.m/s 2 2 C. kg.m /s 2 2 D. kg. m . s 2 E. .kg. s /m C 45. If a spri

37、ng is doubled in len gth, the n the pote ntial en ergy stored in the spri ng will be A. double B. halved C. quadrupled D. quartered E. the same as before C 46. A 5 kg mass is moving horiz on tally at 10 m/s along a horiz on tal floor that can be con sidered frictionl ess .It collides aith a light sp

38、ri ng at rest.The spri ng compresses by 5 meters un til the mass stops. What is the value of the spri ng con sta nt k? A. 10N/m B. 15 N/m C. 20 N/m D. 250 N/m E. 4.5 N/m C 47. Which of the followi ng expressi on s,where p represe nts the lin ear mome ntum of the particle,is equivale nt to the kin et

39、ic enery of a moving particle? 2 A. mp r2 B. m /2p C. 2p/m D. p/2m E. p 2 /2m E 48. Two carts havi ng masses 1.5kilograms and 0.7 kilogram, respectively, are in itially at rest and are held together by a compressed massless spri ng. When released,the 1.5-kilogram cart moves to the left with a veloci

40、ty of 7 meters per sec ond . What are the velocity and direct ion of the 0.7-kilogram cart? A. 15m/s right B. 15m/s left C. 7m/s left D. 7m/s right E. Om/s A 49. The product of an object sinstantancous momentum and its acceleration is equato its A. applied force B. kin etic en ergy C. power output D

41、. net force E. displaceme nt C 50. A ball with a mass of 0.15kilogram has a velocity of 5 meters per second . It strikes a wall perpe ndicularly and bounces off straight back with a velocity of 3 metters per sec ond . The ball un derwe nt a cha nge in mome ntum equal to A. 0.30kg.m/s B. 1.20 kg.m/s

42、C. 0.15 kg.m/s D. 5 kg.m/s E. 7.5 kg.m/s B 51. What brak ing force is supplied to a 3000-kilogram kilogram m car traveli ng with a velocity of 35 meters per sec ond that is stopped in 12 sec on ds? A. 29400N B. 3000N C. 8750N D. 105000N E. 150N C 52. A 0.1 kilogram baseball is throw n with a velocit

43、y of 35 meters per sec ond . The batter hits it straight back with a velocity of 60 meters per second . What is the magnitude of the average impulse exerted on the ball by the bat? A. 3.5N.s B. 2.5 N.s C. 7.5 N.s D. 9.5 N.s E. 12.2 N.s D 53. A 1- kilogram object is movi ng with a velocity of 6 meter

44、s per sec ond to the right . It collides and sticks to a 2- kilogram object moving with a velocity of 3 meters per second in the same directio n. How much kin etic en ergy was lost in the collisi on? A. 1.5j B. 2j C. 2.5j D. 3j E. 0j D 54. A 2- kilogram mass moving with a velocity of 7 meters per se

45、cond collides elastically with a 4- kilogram mass movi ng in the opposite direct ion at 4 meters per sec ond . The 2- kilogram mass reverses direct ion after the collisi on and has a new velocity of 3 mters per sec ond . What is the new velocity of the 4- kilogram mass? A. -1m/s B. 1m/s C. 6m/s D. 4

46、m/s E. 5m/s B 55. A mass m is attached to a massless spring with a force constant k .The mass rests on a horizontal frictionless surface. The system is compressed a distanee x from the spring initial position and then released. The momentum of the mass when the spring passes its equilibrium positi o

47、n is give n by A. x mk B. x k/m f C. x m/ k D. x . k2 m E. xmk A 56. Duri ng an in elastic collisi on betwee n two balls, which of the followi ng stateme nts is correct? A. Both mome ntum and kin etic en ergy are con served B. Mome ntum is con served,but kin etic en ergy is not con served C. Mome nt

48、um is not con served,but kin etic en ergy is con served D. Neither mome ntum nor kin etic en ergy is con served E. Mome ntum is sometimes con served , but kin etic en ergy is always con served B 57. What is the value of g at a height above Earth surface that is equal to the radius of Earth? A. 9.8N/

49、kg B. 4.9 N/kg C. 6.93 N/kg D. 2.45 N/kg E. 1.6 N/kg D 58. Another planet has half the mass of Earth and half the radius.Compared to the acceleration due to gravity near the surface of Earth,the acceleration of gravity near the surface of this other plant is A. twice as much B. on e-fourth as much C

50、. half as much D. the same E. zero A 59. The gravitational force between two objects is F.lf one of the masses is doubled while the dista nee betwee n them is also doubled, the new gravitati onal force betwee n them will be equal to A. F B. 2F C. F/2 D. 4F E. F/4 B 60. Kepler first law states that t

51、he planets orbit the sun in A. eireles B. parabolas C. ellipses D. hyperbolas E. eyeloids C 61. Whieh of the followi ng is equivale nt to the gravitati onal field stre ngth g? A. N.m B. N.kg C. (N.m)/kg D. N/m E. N/kg E 62. Accord ing to Kepler laws, as a pla net gets farther away from the sun , its

52、 kin etie en ergy will A. i ncrease B. deerease C. remai n the same D. the an swer depe nds on the mass of the pla net E. the an swer depe nds on the mass of the sun B 63. Whieh of the followi ng stateme nts is correct about a satellite in geos yn-chronous orbit abo unt Earth? A. lt orbital period i

53、s equal to approximately B. lts orbital period is approximately equal to 365 days C. lt orbit must take it over the n orth pole D. lts orbit must always gollow the equator E. N one of the above are correct A 64. Kepler second law of planetary motion is a consequenee of the law of conservation of A.

54、li near mome ntum B. charge C. en ergy D. mass E. a ngular mome ntum E 65. What is the gravitatio nal force of attract ion betwee n two trucks, each of mass 20000kilograms, separated by a dista nee of 2 meters? A. 0.0057N B. 0.0013N C. 0.0067N D. 1.20N E. 0N C 66. The gravitatio nal force betwee n t

55、wo masses is 36nn ewt ons .If the dista nee betwee n the masses is tripled , the force of gravity will be A. the same B. 18N C. 9N D. 4N E. 27N D 67. Two satellites orbit the earth in circular orbits,each traveli ng at a con sta nt speed . The radius of satellite A/s orbit is R,a nd the radios of sa

56、tellite B orbit is 3R . Both satellites have the same mass. How does Fa ,the centripetal force on satellite A,compare with F b ,the cntriptal force on satellite B? A. F =9 F b ab B. F =3 F b ab C. F = F ab D. 3F = F ab E. 9F A 68. The mea n dista nee from Saturn to the sun is 9 times greater tha n t

57、he mea n dista nee from Earth to the sun .How long is a Satur n year? A. 18 Earth years B. 27 Earth years C. 81 Earth years D. 243 Earth years E. 729 Earth years B 69. A moon of Jupiter has a n early circular orbit of radius R and an orbit period of T. Which of thefollow ing expressi ons give the ma

58、ss of Jupiter? 2r 二 A. - T , 2 4r : B. - T C. GT D. 4r2二2 GT2 E. 4 二 2r3 GT2 E 70. An object of mass 0.5kg , moving in a circular path of radius 0.25 m. experiences a centripetal 2 acceleration of constant magnitude 9m/s , What is the object sangular speed? A. 2.3rad/s B. 4.5 rad/s C. 6 rad/s D. 12

59、rad/s E. Ca nnot be determ ined from the in formatio n give n C 71. Which of the followi ng best describes a perfectly in elastic collisi on free of external forces? A. Total li near mome ntum is n ever con served B. Total lin ear mome ntum is sometimes (but not always) con served C. ki netic enery

60、is n ever con served. D. kin etic enery is sometimes(but not always) con served. E. kin etic enery is always con served C 72. Two objects move toward each other, collide,a nd separate. If there was no net exter nal force acting on the objects,but some kin etic en ergy was lost,the n A. the collisi o