**31. According to Lami’s theorem**

- three forces acting at a point will be in equilibrium
- three forces acting at a point can be represented by a triangle, each side being proportional to force
- 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
- 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**

- resultant couple
- moment of the forces
- resulting couple
- moment of the couple
- 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 **

- one-fourth of the height above base
- one-third of the height above base
- three-eighth of the total height above base
- one-half of the total height above the base
- none of the above

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

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

- kg m
^{2} - m
^{4} - kg/m
^{2} - m
^{3} - kg/m
^{4}

Ans. b) m^{4}

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 m ^{2}**

**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**

- area of contact
- shape of surfaces
- strength of surfaces
- nature of surface
- 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**

- towards the wall at its upper end
- away from the wall at its upper end
- upwards at its upper end
- downwards at its upper end
- 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**

- towards the wall at its upper end
- away from the wall at its upper end
- upwards at its upper end
- zero at its upper end
- none of the above

Ans. d) zero at its upper end.