11. A ladder is resting on a smooth ground and is leaning against a rough vertical wall. The frictional force will act:

(a) Upwards at its upper end

(b) Towards the wall at its upper end

(c) Away from the wall at its upper end

(d) Downwards at its upper end

Answer: (a)

12. When a body is in equilibrium under the action of coplanar concurrent forces, the algebraic sum of:

1. All forces acting on the body is zero

2. Moments of forces about any fixed point is non-zero

3. Moments of forces about any fixed point is zero

4. All forces acting on the body is non-zero

Which of the above statements is/are correct?

(a) 1 only

(b) 2 only

(c) 1 and 3 only

(d) 2 and 4 only

Answer: (c)

13. Creep of rock at the maximum expected pressure should be measured by keeping the pressure constant for:

(a) 2-3 hours

(b) 2-3 months

(c) 2-3 minutes

(d) 2-3 days

Answer: (d)

14. 

Answer: (d)

15. A solid circular shaft of radius 𝑟 and length 𝑙 is fixed at one end and free at the other end. A torque 𝑇 is applied at the free end. The shear modulus of the material is 𝐺. The angle of twist at the free end is:

Answer: (c)

16. An I section of depth 100 mm has an area of 1000 𝑚𝑚 2. A plate of 100 mm ×5 mm is then welded to the top flange of this beam. This composite section is used as a simply supported beam. What will be the ratio of the maximum tensile stress to the maximum compressive stresses on this composite section under pure bending of beam?

(a) 1.22

(b) 1.30

(c) 1.41

(d) 1.59

Answer: (d)

17. Shear centre refers to:

1. The point through which loading should pass such that there is only bending and no twisting

2. It is the point through which resultant shear stress passes

Which of the above statements is/are correct?

(a) 1 only

(b) 2 only

(c) Neither 1 nor 2

(d) Both 1 and 2

Answer: (d)

18. In Bord and Pillar panels worked in conjunction with hydraulic stowing, line of extraction preferred is:

(a) Steep diagonal

(b) Step diagonal

(c) Straight line

(d) Diagonal

Answer: (b)

19. 

Answer: (d)

20. Consider the following statements with reference to built-up-edge on a cutting tool while machining:

1. It increases the frictional resistance

2. It causes increased power consumption

3. It results in poor surface finish

Which of the above statements are correct?

(a) 1, 2 and 3

(b) 1 and 2 only

(c) 1 and 3 only

(d) 2 and 3 only

Answer: (a)