21. Which of the following is not a scalar quantity

1. Time
2. mass
3. volume
4. density
5. acceleration

Ans. e) Acceleration

22. According to principle of transmissibility of forces, the effect of a force upon a body is the same at every point in its line of action. (True/False)

Ans. True

23. Which of the following is a vector quantity

1. energy
2. mass
3. momentum
4. angle
5. speed

Ans. Momentum

24. A number of forces acting at a point will be in equilibrium if sum of resolved parts in any two perpendicular direction are both zero (yes/no)

Ans. Yes

25. Two non-co linear parallel equal forces acting in opposite direction constitute a couple (yes/no)

Yes.

26. According to principle of moment, if a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero. 

27. Which of the following is not a vector quantity

1. weight
2. velocity
3. acceleration
4. force
5. moment

Ans. a) weight

28. if a rigid body is in equilibrium under the action of three forces then,’

1. these forces are equal
2. the lines of action of these forces meet in a point
3. the line of action of these forces are parallel
4. (b) and (c) above
5. none of above

Ans. d)

29. D’Alembert’s principle is used for

1. reducing the problem of kinetics to equivalent statics problem
2. determining stresses in the truss
3. stability of floating bodies
4. designing safe structures
5. solving kinematic problem

Ans. a) reducing the problem of kinetics to equivalent statics problem.

30. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if 

1. the floor is smooth, the wall is rough
2. the floor is rough, the wall is smooth
3. the floor and wall both are smooth surfaces
4. the floor and wall both are rough surfaces
5. will be in equilibrium under all conditions

Ans. c) the floor and wall both are smooth surfaces