31. According to Lami’s theorem

1. three forces acting at a point will be in equilibrium
2. three forces acting at a point can be represented by a triangle, each side being proportional to force
3. if three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium
4. if three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two

Ans. d)

32. Two coplanar couples having equal and opposite moments : can not balance each other.

34. A framed structure is perfect if it contains members equal to: 2n-3

35. The product of either force of couple with the arm of the couple is called

1. resultant couple
2. moment of the forces
3. resulting couple
4. moment of the couple
5. none of the above

Ans. d) moment of the couple

36. The center of gravity of a uniform lamina lies at the mid point of its axis (true/false)

Ans. True

37. Center of gravity of a solid cone lies on the axis at the height : one-fourth of the total height above base.(True/false)

Ans. True.

38. Center of percussion is the point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis.(true/false)

Ans. True

39. The center of gravity of a thin hollow cone lies on the axis at a height of 

1. one-fourth of the height above base
2. one-third of the height above base
3. three-eighth of the total height above base
4. one-half of the total height above the base
5. none of the above

Ans. b) one-third of the height above base

40. The units of moment of inertia of an area are

1. kg m²
2. m⁴
3. kg/m²
4. m³
5. kg/m⁴

Ans. b) m⁴

Engineering Mechanics or Applied Mechanics Important Question

41. The center of percussion of the homogeneous rod of length L suspended at the top will be: 2L/3.

42. The center of gravity of a triangle lies at the point of concurrence of the medians.

43. The units of moment of inertia of mass are: kg m²

44. The possible loading in various members of framed structures are compression or tension.

45. if a suspended body is struck at the center of percussion, then the pressure on die axis passing through the point of suspension will be zero.

46.  Angle of friction is the angle between normal reaction and the resultant of normal reaction and the limiting friction. (True)

47. The coefficient of friction depends on

1. area of contact
2. shape of surfaces
3. strength of surfaces
4. nature of surface
5. all of the above

Ans. d) nature of surface.

48. The ratio of limiting friction and normal reaction is known as coefficient of friction.

49. On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be

1. towards the wall at its upper end
2. away from the wall at its upper end
3. upwards at its upper end
4. downwards at its upper end
5. none of the above

Ans. c) upwards at its upper end.

50. On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be

1. towards the wall at its upper end
2. away from the wall at its upper end
3. upwards at its upper end
4. zero at its upper end
5. none of the above

Ans. d) zero at its upper end.