51. The algebraic sum of moments of the forces forming couple about any point in their plane is A. Equal to the moment of the couple B. Constant C. Both of above are correct D. Both of above are wrong Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
52. A force acting on a body may A. Introduce internal stresses B. Retard its motion C. Change its motion D. All of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
53. The angle which an inclined plane makes with the horizontal when a body placed on it is about to move down is known as angle of A. Friction B. Limiting friction C. Repose D. Kinematic friction Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
54. When trying to turn a key into a lock, following is applied A. Coplanar force B. Non-coplanar forces C. Moment D. Couple Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
55. Which is the correct statement about law of polygon of forces? A. If any number of forces acting at a point can be represented by the sides of a polygon taken in order, then the forces are in equilibrium B. If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium C. If a polygon representing forces acting at a point is closed then forces are in equilibrium D. If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, then the forces are in equilibrium Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
56. The effort required to lift a load W on a screw jack with helix angle $$\alpha $$ and angle of friction $$\varphi $$ is equal to A. $${\text{W}}\tan \left( {\alpha + \varphi } \right)$$ B. $${\text{W}}\tan \left( {\alpha - \varphi } \right)$$ C. $${\text{W}}\cos \left( {\alpha + \varphi } \right)$$ D. $${\text{W}}\sin \left( {\alpha + \varphi } \right)$$ Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
57. In actual machines A. Mechanical advantage is greater than velocity ratio B. Mechanical advantage is equal to velocity ratio C. Mechanical advantage is less than velocity ratio D. Mechanical advantage is unity Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
58. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if A. The floor is smooth and the wall is rough B. The floor is rough and the wall is smooth C. The floor and wall both are smooth surfaces D. The floor and wall both are rough surfaces Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
59. The C.G. of a right circular solid cone of height h lies at the following distance from the base A. $$\frac{{\text{h}}}{2}$$ B. $$\frac{{\text{h}}}{3}$$ C. $$\frac{{\text{h}}}{6}$$ D. $$\frac{{\text{h}}}{4}$$ Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
60. According to principle of moments A. If a system of coplanar forces is in equilibrium, then their algebraic sum is zero B. If a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero C. The algebraic sum of the moments of any two forces about any point is equal to moment of the resultant about the same point D. Positive and negative couples can be balanced Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board