ECE198 Drill 11 Mechanics

8/12/2019 ECE198 Drill 11 Mechanics

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MECHANICS(DRILL 11)

*RED colors are 5 points

1.If the support is a rocker, in drawing tha free-body diagram, the reaction force has __

unknowns(s)

Select one:

a. 2

b. 1

c. 4

d. 3

2. A stone is thrown vertically upward and returns to earth in 10 sec. What was its initial

velocity?Select one:

a. 37.2 ft/s

b. 161 ft/s

c. 98.1 ft/s

d. 9.81 ft/s

3. Determine the work done by the force when it is subjected to the displacement indicated.

Select one:

a. 0J

b. 20.0J

c. 17.32J

d. 5.00J

4. Which of the following is FALSE?

Select one:

a. A resultant couple moment is simply the vector sum of all the couple moments of the system.

b. The forces exerted by your hand on a screw-driver is an example of a force-couple system.

c. A couple moment is produced by two noncollinear forces which are equal in magnitude but

opposite in direction.


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d. A couple moment causes different effect of rotation on a body when it is applied at

different point.

5. The triple scalar product u . ( r x F ) results in

Select one:

a. a unit inventor.b. zero.

c. a scalar quantity ( + or - ).

d. a vector quantity.

6. It is convenient to express the velocity and the acceleration vectors using radial and

transverse components in

Select one:

a. polar coordinates

b. cylindrical coordinates

c. rectangular coordinates

7. If expressed in Cartesian vector form, F1 is

Select one:a. (2.17 i + 3.75 j + 4.33 k) kN

b. (4.33 i + 3.54 j + 4.33 k) kN

c. (4.33 i + 3.75 j + 2.17 k) kN

d. (2.50 i + 3.54 j + 2.50 k) kN

8. F in unit vector notation in


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Select one:

a. 100j N

b. -100i N

c. 100i N

d. -100j N

9. The gusset plate G of a bridge joint is subjected to the two member forces at A and B. If the

force at B is horizontal and the force at A is directed at 0 = 30o, determine the magnitude and

direction of the resultant force.

Select one:

a. R252 N, O97.5o

b. R458 N, O82.5o

c. R252 N, O82.5o

d. R458 N, O97.5o

10. The 10 Kg block is released from rest at A. Select the equation that represents the reduced

form oa the conservation of energy theorem, necessary to determine the maximum

compression h in the spring at B. Place the datum at A.

Select one:

a. 0=-98.1h + 50h2

b. 0=-98.1h - 98.1 - 50h2

c. 0=-98.1 - 98.1h +50h2

d. 0=-98.1 - 50h2

11. At a given instant, blocks A and B have the motion shown. The acceleration of block B with

respect to A is


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Select one:

a. 1i m/s

b. -1i m/s

c. 3i m/s

d. none of these

12. The resultant of the three forces in figure 1 is

Select one:

a. 896N, 51.1o

b. 638N, 51.1o

c. 638N, 38.9o

d. 896N, 38.9o

13. The magnitude of F for each of the two forces acting on the outer circle, so that they createthe same couple moment as that created by the 100-N forces acting on the inner circle is


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Select one:

a. 40N

b. 25 N

c. 80 N

d. 10 N

14. If s = (4t2) m, calculate the particle's acceleration at t = 2s.

Select one:

a. 0 m/s2

b. 32 m/s2

c. 8 m/s2

d. 16 m/s2

15. Frames are different as compared to trusses since they have _______.

Select one:

a. at least one multiforce member

b. only multiforce members

c. only two-force members

d. at least ane two-force member

16. The value of R in the figure is

Select one:

a. 4.43 m

b. 6.00 m

c. 9.81 m

d. 4.91 m

17. A ball is thrown horizontally from A with a speed of vA = 6m/s as shown. If it strikes the

ground in t = 1s. Determine the height h.


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Select one:

a. 10.00 m/s2

b. 19.81 m/s2

c. 19.60 m/s2

d. 9.81 m/s2

21. If the end of the cable at A is pulled down at a speed of 2 m/s. The speed with which block B

rises is

Select one:

a. -1 m/s

b. 1 m/s

c. -2 m/s

d. 2 m/s

22. A rectangular system is said to be right-handed if

Select one:

a. the thumb of the right hand points in the direction of the positive z axis when the right hand

fingers are curled about this axis and directed from the -x axis towards the +y axis.

b. the thumb of the right hand points in the direction of the positive z axis when the right hand

fingers are curled about this axis and directed from the +x axis towards the -y axis.

c. the thumb of the right hand points in the direction of the positive z axis when the right

hand fingers are curled about this axis and directed from the +x towards the +y axis.

d. the thumb of the right hand points in the direction of the negative z axis when the right hand

fingers are curled about this axis and directed from the +x axis towards the +y axis.

23. In the FBD at the pin given, member GC must be in

Select one:

a. Compression

b. cannot be cetermined

c. tension


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24. Given the s - t graph. Calculate the particle's velocity when t = 1s.

Select one:

a. 1 m/s

b. 4 m/s

c. 2 m/s

d. 0.5 m/s

25. In the method of joints, typically _______ equations of equilibrium are applied at every

joint.

Select one:

a. two

b. four

c. six

d. three

26. The dot product of two vectors results in a _______ quantity

Select one:a. zero

b. vector

c. complex

d. scalar

27. If the numbers of unknown forces is more than the equations that can be used, the system

is said to be

Select one:

a. statically deformed

b. statically determinate

c. statically indeterminate

d. statically undeterminate

28. If the cable has a tension of 3 N, determine the acceleration of block B.


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Select one:

a. 4.36 m/s2

b. 8.21 m/s2

c. 4.26 m/s2

d. 8.31 m/s2

29. At the bottom of a loop, the speed of the roller coaster is 587 ft/s. This causes a normal

acceleration of 9g ft/s2. The radius of the loop is

Select one:

a. 3.83x104 ft

b. 3.90x103 ft

c. 552 ft

d. 1380 ft

30. A stone is dropped from the roof of a building 35m high. It will reach the ground after

Select one:

a. 2.67s

b. 1.69s

c. 1.43s

d. 1.33s

31. What is the particle's position at the end of 4s?

Select one:

a. 40mb. 30m

c. 20m

d. 10m


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32. The moment of the couple's two forces about point A is

Select one:

a. 300 N-m clockwise

b. 200 N-m clockwise

c. 100 N-m clockwise

d. 250 N-m clockwise

33. The moment of 100-N force about O is

Select one:

a. (70.7k) Nm

b. (-70.7k) Nm

c. (-141.4k) Nm

d. (141.4k) Nm

34. In figure 25, is the rod a two-force member?


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Select one:

a. Yes

b. No

35. Engineering mechanics is formulated on the basis of Newton's

Select one:

a. Second Law

b. Three Laws of Motionc. Third Law

d. First Law

36. The correct FBD of the figure is

a.


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b.

c.

d.

37. Fr can be determined by

Select one:

a. Pythagorean Theorem

b. Sin Lawc. Cosine Law

38. The magnitude of Fr in figure 20 is


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Select one:

a. -500N

b. 500N

c. -250N

d. 250N

39. The frictional effects of the air on the blades of the standing fan creates a couple moment

of Mo = 6 N-m on the blades. The value of couple forces at the base of the fan so that the

resultant couple moment on the fan is zero is

Select one:

a. 1.8N

b. 80N

c. 20N

d. 40N

40. The magnitude and direction of the moment of the force of the movement if the force at A

about point P.


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Select one:

a. Mp=500 Nm

b. Mp=400 Nm

c. Mp=200 Nm

d. Mp=400 Nm

41. For this truss, determine the number of zero-force members.

Select one:

a. 1

b. 2

c. 3

d. 0

42. The speed of block A if block B has an upward velocity of 6 ft/s is

Select one:

a. 2 ft/s

b. 12 ft/s

c. 18 ft/sd. 1.5 ft/s

43. I ft-lb is equivalent to ___Joules.

Select one:

a. 1

b. 1.356

c. 550

d. 746

44. This relates displacement, velocity, acceleration and time without reference to the cause of

motion.Select one:

a. Kinematics

b. Kinetics

c. Mechanics

d. Dynamic


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45. A 200kg crate is on top of a 5m-hill. Its potential energy with respect to the bottom of the

hill is

Select one:

a. 1.000x103J

b. -9.80x103J

c. 9.80x103Jd. 5.00x103J

46. For a particle in space in static equilibrium, ___ equations can be used.

Select one:

a. 1

b. 3

c. 2

d. 4

47. Newton's ____ law forms the basis of the study of dynamics.

Select one:

a. 2nd

b. 3rd

c. 1st

d. gravitation

48. The ball has a mass of 20 kg and a speed of v = 30 m/s at the instant it is at its lowest point.

Determine the tension in the cord at this instant.

Select one:

a. 1596 N

b. 2196 N

c. 1796 N

d. 1996 N

49. If a = (2t) m/s2, where t is in seconds, calculate the particle's velocity when t = 2s. When t =

0, Vo = 2m/s.

Select one:

a. 0 m/s

b. 8 m/s

c. 6 m/s

d. 2 m/s


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50. In the pendulum bob, kinetic energy is greatest

Select one:

a. at all points of its swing

b. midway between the end point of its swing and the bottom of its swing

c. at the left end point of its swing

d. at the bottom of its swing

51. In the figure, which equation relates the position of the blocks?

Select one:

a. 2XA + XB + XC=L

b. XA + XB + 2XC=L

c. XA + 2XB + XC=L

d. XA + XB + XC=L

52. Given: figure 1 as shown, the total horizontal component of 400N force is

Select one:

a. 400N cos 30o

b. 400N sin 30oc. -400N cos 30o

d. -400N sin 30o

53. A general systemt of forces and couple moments acting on a rigid body an be reduced to a

____.

Select one:

a. single force and two moments.


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Select one:

a. 3s

b. 6s

c. 16s

d. 12s

58. Given the a-t curve, the change in_____ between t1 and t2 is equal to the area under the a-

t curve between t1 and t2.

Select one:

a. timeb. position

c. velocity

d. acceleration

59. Which equation of equilibrium allows you to determine FB right away?

Select one:a. E MA=0

b. Any one of the choices

c. E Fy=0

d. E Fx=0

60. In polar coordinate, the radial acceleration is defined as

Select one:

a. r - 2r

b. r + 2r

c. r - r2d. r

61. Kinetic energy results from ______.

Select one:

a. Displacement

b. friction

c. velocity


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d. gravity

62. A 20 lb block is moving along a smooth surface. If the normal force on the surface at A is 10

lb, the velocity is______.

Select one:

a. 10.6 ft/sb. 12.6 ft/s

c. 7.6 ft/s

d. 9.6 ft/s

63. To determine Fr in the figure, we use

Select one:

a. Cosine Law

b. None of these

c. Pythagorean Theorem

d. Sine Law

64. Select the equation which relates the position of the end of the cable B to the position of

block A.

Select one:

a. SB + 3SA=L

b. SB + SA=L

c. 2SB + SA=L

d. SB + 2SA=L


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65. The magnitude of the couple shown is

Select one:

a. 1200N-m CW

b. 400N-m CCW

c. 1200N-m CCW

d. 800N-m CW

66. A 10 lb particle has forces of F1 = (3i + 5j) lb and F2 = (-7i + 9j) lb acting on it. Determine the

acceleration of the particle.

Select one:a. (-4 i + 14 j) ft/s2

b. (-0.4 i + 1.4 j) ft/s2

c. (-12.9 i + 45 j) ft/s2

d. (13 i + 4 j) ft/s2

67. A 10 kg blocks rests on a smooth surface, compute the blocks initial acceleration.

Select one:

a. 2 m/s2

b. 5 m/s2

c. 0 m/s2

d. 10 m/s2

68. Calculate the power developed by the 100 N which acts on the 10 Kg block. The block has aspeed of 2 m/s.


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Select one:

a. 100 W

b. 250 W

c. 200 W

d. 50 W

69. Which of the following is not a curvilinear motion?

Select one:

a. passenger in a turning ferris wheel

b. a rotating disc

c. projectile

d. satellite's motion

70. A ball is thrown at an angle of 45o with horizontal at an initial speed of VA = 10m/s. What is

the maximum height it can attain?

Select one:

a. 9.81 m

b. 0.722 m

c. 2.55 m

d. 4.91 m

71. Given: the v-t graph, the acceleration of the particle when t= 3s is

Select one:

a. 27.5 m/s2

b. -5.00 m/s2

c. 5.00 m/s2


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b. (100i)N, (100k)Nm

c. (-100i)N, (100k)Nm

d. (100i)N, (-100k)Nm

78. A ball is thrown horizontally from A with the speed of vA = 6 m/s. If it strikes the ground in t

= 1.52 s, the height h is

Select one:

a. 9.12 m

b. 8.91 m

c. 11.33 m

d. 3.95 m

79. The moment of the force at A about point P is

Select one:

a. Mp=18.43 kN-m(counterclockwise)


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b. Mp=18.48 kN-m (counterclockwise)

c. Mp=33.5 kN-m(clockwise)

d. Mp=35.3kN-m(clockwise)

80. Internal forces are not included in an equation of motion analysis because the internal

forces are ______.Select one:

a. equal and opposite and do not affect the calculations.

b. not important.

c. negligibly small.

d. equal to zero.

81. The maximum number of unknowns for three-dimensional rigid body is

Select one:

a. 5

b. 6

c. 4

d. 3

82. The position vector r is represented by

Select one:

a. (2i + 4j + 4k) m

b. (4j + 3k) m

c. (3i + 4j) m

d. (-2i - 4j

e. 3k) m

83. A particle P is travelling around a circular path such that at the instant considered, thespeed is 3m.s and increasing at 4m/s2. The magnitude of the particle's acceleration at that

instant is


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Select one:

a. 0 m/s2

b. 5.00 m/s2

c. 3.00 m/s2

d. 4.00 m/s2

84. When t = 0, s = 0.5, v = 1m/s. If v = (3t + 1) m/s, where t is in seconds, compute the distance

s traveled by the particle when t = 1s.Select one:

a. 5m

b. 3m

c. 4.5m

d. 3.5m

85. The particle shown in the figure travels from A to B in 1s, it then travels from B to C in 1s.

What is the average velocity?

Select one:

a. 2m/s

b. 1 m/sc. -5 m/s

d. -1m/s


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b. -200N(4m) + F(2m)=0

c. -200N(4cos30om) + F(2m)=0

d. -20N(4cos30om) + F(2m)=0

89. The work done by the spring in the figure is

Select one:

a. 25J

b. 10J

c. -50J

d. 100J

90. The magnitude and direction of the couple moment is

Select one:

a. M=3900 lb-ft CW

b. M=3120 lb-ft CCW

c. M=3900 lb-ft CCW

d. M=3120 lb-ft CW


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91. Given the v - t graph. Calculate the particle's acceleration when t = 3s.

Select one:

a. -1.67 m/s2

b. -10 m/s2

c. -5 m/s2

d. -15 m/s2

92.

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ECE198 Drill 11 Mechanics

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