1. A free body diagram shows the forces and moments acting on an isolated body. A force couple system can replace a single force with an equal force and couple at another point. 2. A couple is a pair of two equal and unlike parallel forces that tends to rotate a body. Varignon's theorem states the sum of the moments of all forces about a point equals the moment of their resultant about that point. 3. Supports include roller, hinged, and fixed. Equations of equilibrium in 2D are the sum of horizontal forces equals zero, the sum of vertical forces equals zero, and the sum of moments equals zero.

1. UNIT II EQUILIBRIUM OF RIGID BODIES-2 Marks
1. What is free body diagram?
The body which has been so separated or isolated from the surrounding
bodies is called free body. The sketch showing the forces and moments acting on a
body is called as free body diagram.
2. What is meant by a force couple system?
A force acting at a point in a rigid body can be replaced by an equal `Force and
couple` at any other point in the rigid body. The combination of force and couple is
referred to as a force couple system.
3. Define couple.
A pair of two equal and unlike parallel forces is known as couple. Couple has a
tendency to rotate the body.
4. State Varignon`s theorem.
It states that “sum of the moment of the all the forces about a point is equal to
moment of their resultant about the same point”.
ie.,F1d1+ F2d2+ F3d3=Rd
5. State the different types of supports and its reactions.
1. Roller support or Rocker support,
2. Hinged or pin support,
3. Fixed support.
6. Write the equations of equilibrium of a rigid body in two dimensions.
1. Summation of all the horizontal forces is zero. (ΣH=0)
2. Summation of all the vertical forces is zero. (ΣV=0).
3. Summation of all the moments is zero. (ΣM=0).
7. Find the magnitude and location ofthe single equivalent forceforabeam AB oflength
8m having a pint C at 3m from A subjected the following forces
a) An upward force of 10N at A
b) A downward force of 10N at C
c) An upward force of 40N at B

2. 9. A Uniform ladder of weight 'W' leans against a vertical wall. Assuming the contact
surfaces as rough, draw the free body diagram of the ladder with necessary
assumptions.
10.List the different types of beams?
1. Simply supported beam
2. Overhanging beam
3. Continuous beam
4. Cantilever beam
5. Fixed beam
11. Find the moment of the 100 N force about point A and B
12. Define moment.
Moment of a force about an axis is the ability of the force to rotate a
body about the same axis in addition to the effect of the force on a body.
Moment due to force on a plane about an axis perpendicular to it at any
point is equal to the product of the magnitude of the force and the perpendicular
distance. Unit is N-m.
Moment (M) = force x perpendicular distance