Applied Mechanics C CECE2110N

Diploma 2nd Year – Architectural Engineering

Review – Quiz (Chapter 1)

1. What is Mechanics?

Mechanics

“Branch of Science deals with the effects of forces on objects which are at rest or motion.”

2. What is statics?

Statics

“Branch of Mechanics deals with the particle or body at rest”.

3. What is Dynamics?

Dynamics

“Branch of Mechanics deals with the particle or body at motion”.

4. What is a rigid body and deformable body?

Rigid Body

“A body does not deform under the action of forces”.

Deformable Body

“A body does deform under the action of forces”.

5. What is Force?

Force

“External Agency which changes or tends to change the state of the body”.

6. What is the unit of Force in SI system?

Unit of Force in SI system

Unit of Force : Newton (N)Basic Unit : Kg. (m/s2)

7. What is the unit of mass?

Mass

• Quantity of matter possessed by a body or particle.

• Mass is a scalar quantity.• Mass never changes from place to place.

Unit of Mass : Kg

8. What is the unit of Weight?

Weight

• Force exerted by the earth on the particle or body.

• Weight is a Vector quantity.• Weight changes according to gravitational

acceleration (changes from place to place).

Unit of Weight : Newton (N)Basic Unit : Kg. (m/s2)

9. What is Equilibrium of a body?

Equilibrium of a body

“ A Body is said to be in equilibrium, when the resultant of forces acting on the body is zero.”

“If the body is in equilibrium, it will continue to remain in state of rest or in of uniform motion”

10. What is Equilibrant force?

Equilibrant Force

“ A force with keep the body under equilibrium”

“Equilibrant Force is equivalent to the resultant force but in opposite direction”

11. What is Concurrent force system?

Concurrent Force System

“ Line of action of all the forces pass through a common point of intersection is called

concurrent force system.”Example:

12. State the equilibrium conditions.

Equilibrium Conditions

(i) Resultant Force, R = 0 i.e.,(ii) Sum of Horizontal forces equal to zero

i.e., (iii)Sum of Vertical forces equal to zero

i.e.,

XF 0

YF 0

13. State Lami’s Theorem

Lami’s Theorem

“In a concurrent system, If 3 forces are acting on a particle are in equilibrium, then each force is proportional to the sine of the included angle

between the other 2 forces.”

14. What is Free Body Diagram?

Free Body Diagram

“Diagram of a separated body showing all the external forces acting on the body and their

reactions .”

end of quiz

Discussions made further

• Parallelogram law of forces• Triangular law of forces• Polygon law of forces• Drawing free body diagram• Problems involving – concurrent forces solving

using (a) Equilibrium conditions (b) Lami’s Theorem