Applied Mechanics and Graphic Statics MCQ Solved Paper for RBI Assistant

21. A number of forces acting simultaneously on a particle of a body
A. May not be replaced by a single force
B. May be replaced by a single force
C. May be replaced by a single force through C.G. of the body
D. May be replaced by a couple
Answer : B

22. Total no of instantaneous centres of a machine having n links, is
A. n/2
B. n
C. (n - 1)
D. n (n - 1)/2
Answer : D

23. A satellite is said to move in a synchronous orbit if it moves at an altitude of 36, 000 km with a maximum velocity of about
A. 7000 km per hour
B. 8000 km per hour
C. 9000 km per hour
D. 11,000 km per hour
Answer : @

24. The apparent weight of a man in a moving lift is less than his real weight when it is going down with
A. Uniform speed
B. An acceleration
C. Linear momentum
D. Retardation
Answer : B

25. Centre of gravity of a thin hollow cone lies on the axis of symmetry at a height of
A. One-half of the total height above base
B. One-third of the total height above base
C. One-fourth of the total height above base
D. None of these
Answer : B

26. A ball of mass 1 kg moving with a velocity of 2 m/sec collides a stationary ball of mass 2 kg and comes to rest after impact. The velocity of the second ball after impact will be
A. Zero
B. 0.5 m/sec
C. 1.0 m/sec
D. 2.0 m/sec
Answer : C

27. If two forces each equal to T in magnitude act at right angles, their effect may be neutralised by a third force acting along their bisector in opposite direction whose magnitude will be
A. 2 T
B. 1/2 T
C. ?2 T
D. 3 T
Answer : C

28. The inherent property of a body which offers reluctance to change its state of rest or uniform motion, is
A. Weight
B. Mass
C. Inertia
D. Momentum
Answer : C

29. A 49 kg lady stands on a spring scale in an elevator. During the first 5 sec, starting from rest, the scale reads 69 kg. The velocity of the elevator will be
A. 10 m/sec
B. 15 m/sec
C. 20 m/sec
D. 25 m/sec
Answer : C

30. If the direction of projection bisects the angle between the vertical and the inclined plane, then the range of projectile on the inclined plane is
A. Zero
B. Maximum
C. Minimum
D. None of these
Answer : B

31. One Newton is equivalent to
A. 1 kg. wt
B. 9.81 kg. wt
C. 981 dyne
D. 1/9.81 kg. wt
Answer : D

32. The force polygon representing a set of forces in equilibrium is a
A. Triangle
B. Open polygon
C. Closed polygon
D. Parallelogram
Answer : C

33. If the horizontal range is 2.5 times the greatest height, the angle of projection of the projectile, is
A. 57°
B. 58°
C. 59°
D. 60°
Answer : B

34. The time period of a simple pendulum depends on (i) Mass of suspended particle (ii) Length of the pendulum (iii) Acceleration due to gravity The correct answer is
A. Only (i)
B. Both (ii) and (iii)
C. Both (i) and (iii)
D. All are correct
Answer : B

35. Periodic time of body moving with simple harmonic motion, is
A. Directly proportional to its angular velocity
B. Directly proportional to the square of its angular velocity
C. Inversely proportional to the square of its angular velocity
D. Inversely proportional to its angular velocity
Answer : D

36. If the radius of the earth is 600 km the height of a mountain above sea level at the top of which a beat seconds pendulum at sea level, looses 27 seconds a day, is
A. 500 metres
B. 1000 metres
C. 1500 metres
D. 2000 metres
Answer : D

37. The motion of a particle moving with S.H.M. from an extremity to the other, constitutes
A. Half an oscillation
B. One full oscillation
C. Two oscillations
D. None of these
Answer : A

38. A body of weight w placed on an inclined plane is acted upon by a force P parallel to the plane which causes the body just to move up the plane. If the angle of inclination of the plane is ? and angle of friction is ?, the minimum value of P, is
A. w sin (? - ?)/cos ?
B. w sin (? - ?)/cos ?
C. w cos (? + ?)/cos ?
D. w sin? cos(? - ?)/sin ?
Answer : B

39. In case of S.H.M. the period of oscillation (T), is given by
A. T = 2?/?²
B. T = 2?/?
C. T = 2/?
D. T = ?/2?
Answer : B

40. A rod AB carries three loads of 30 N, 70 N and 100 N at distances of 20 mm, 90 mm and 150 mm respectively from A. Neglecting the weight of the rod, the point at which the rod will balance is
A. 109.5 mm from A
B. 119.5 mm from A
C. 125.5 mm from A
D. 132.5 mm from A
Answer : A

41. A shell travelling with a horizontal velocity of 100 m/sec explodes and splits into two parts, one of mass 10 kg and the other of 15 kg. The 15 kg mass drops vertically downward with initial velocity of 100 m/sec and the 10 kg mass begins to travel at an angle to th horizontal of tan1 x, where x is
A. 3/4
B. 4/5
C. 5/3
D. 3/5
Answer : D

42. Pick up the incorrect statement from the following:
A. The C.G. of a circle is at its centre
B. The C.G. of a triangle is at the intersection of its medians
C. The C.G. of a rectangle is at the intersection of its diagonals
D. The C.G. of a semicircle is at a distance of r/2 from the centre
Answer : D

43. A uniform rod 9 m long weighing 40 kg is pivoted at a point 2 m from one end where a weight of 120 kg is suspended. The required force acting at the end in a direction perpendicular to rod to keep it equilibrium, at an inclination 60° with horizontal, is
A. 40 kg
B. 60 kg
C. 10 kg
D. 100 kg
Answer : C

44. The tension in a cable supporting a lift
A. Is more when the lift is moving downwards
B. Is less when the lift is moving upwards
C. Remains constant whether its moves downwards or upwards
D. Is less when the lift is moving downwards
Answer : D

45. The total time of collision and restitution of two bodies, is called
A. Time of collision
B. Period of collision
C. Period of impact
D. All the above
Answer : D

46. The C.G. of the shaded area of the below figure whose curve OM is a parabola from y-axis, is
A. a/4
B. 3a/4
C. 3b/10
D. 3a/10
Answer : B

47. The angular speed of a car while taking a circular turn of radius 100 m at 36 km/hour, is
A. 0.1 radian/sec
B. 1 radian/sec
C. 100 radian/sec
D. 1000 radian/sec
Answer : A

48. A Second's pendulum gains 2 minutes a day. To make it to keep correct time its length
A. Must be decreased
B. Must be increased
C. Is not changed but weight of the bob is increased
D. Is not changed but weight of the bob is decreased
Answer : B

49. A system of coplanar forces is in equilibrium when
A. Force polygon closes
B. Funicular polygon closes
C. Both force polygon and funicular polygon close
D. All the forces are concurrent
Answer : C

50. One Newton is equivalent to
A. 10⁵ dyne
B. 10⁶ dyne
C. 10⁷ dyne
D. 10⁸ dyne
Answer : A