Two Marks Questions with Answers

Two Marks Questions with Answers

Q.1

Explain free body diagram with one example. 

Ans.:

Free body diagram is the isolated diagram of an object/system of objects/any point in the system in which all forces and couple moments acting on it are shown including support reactions.
For example, consider a ladder of weight W having rollers at its ends as shown in Fig. 4.9.1 (a). Its F.B.D. is shown in Fig. 4.9.1 (b).

Q.2

State the necessary and sufficient conditions for equilibrium of rigid bodies in two dimensions.

Ans.:

The necessary and sufficient conditions for equilibrium of rigid bodies in two dimensions are :

i) Algebraic sum of horizontal components of all forces acting on the body must be zero.

ii) Algebraic sum of vertical components of all forces acting on the body must be zero, and

iii) Algebraic sum of moments due to all forces and couple moments acting on the body must be zero.

Q.3

Write the equations of equilibrium of a rigid body. 

Ans.:

The three equations of equilibrium of a rigid body are :

Q.4

Write the conditions of equilibrium of a system of parallel forces acting in a plane. 

Ans.:

The two conditions of equilibrium of a system of parallel forces acting in a plane are:

i) Algebraic sum of all forces must be zero and

ii) Algebraic sum of moments due to all forces about any point must be zero. 

Q.5 

What are the reactions at a fixed support of a plane beam that the possible?

Ans.:

The reaction at a fixed support of a plane beam consists of

i) A reaction force in the plane which can be represented by its two components (generally taken to be horizontal and vertical) and

ii) A reaction moment.

Q.6

How many scalar equations can be obtained for equilibrium of a rigid body in three dimensions?

Ans.:

Six scalar equations can be obtained for equilibrium of a rigid body in three dimensions.

Q.7 

Name any four types of beams.

Ans.:

Four types of beams are :

i) Simply supported beam

iii) Continuous beam

ii) Cantelever beam

iv) Fixed beam.

Q.8

Determine reaction at A and B for the beam loaded and supported as shown in Fig. 4.9.2.

Ans.:

The FBD of beam is shown in Fig. 4.9.2 (a).

Q.9

Determine reaction at A and B for the beam loaded and supported as shown in Fig. 4.9.3. Moments are act at point C, D and E.

Ans.:

The FBD of beam is shown in Fig. 4.9.3 (a).

Q.10

Determine the reactions at support for the beam loaded and supported as shown in Fig. 4.9.4.

Ans.:

The F.B.D. of beam is shown in Fig. 4.9.4 (a).

Q.11

Find RA and RB of the beam shown in Fig. 4.9.5.

Ans.:

Q.12

Hinged support has two reactions - Justify.

Ans.:

Hinged support or pinned support can resist both vertical and horizontal forces but they cannot resist moment. It means hinged support is restrained against translation. Hence, hinged support has two reactions.