Upcoming SlideShare
×

# 31207

383 views

Published on

0 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

• Be the first to like this

Views
Total views
383
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
3
0
Likes
0
Embeds 0
No embeds

No notes for slide

### 31207

1. 1. © Copyright PCTI Limited 2012 Session 7 MOTION OF RIGID BODY
2. 2. © Copyright PCTI Limited 2012 Topics to be covered • Centre of mass of a Rigid body. • Definition of CM. • CM of some Bodies. • Translational and Rotational Motion. • Moment Of Inertia. • Moment of Inertia of Uniform Bodies. • Memory map of Moment of Inertia. • Theorem of Parallel Axis. • Theorem of Perpendicular Axis. , l l l
3. 3. © Copyright PCTI Limited 2012 Topics To be Covered • Torque and couple . • Rotational and Translational Motion. • Angular Momentum. • Conservation of Angular Momentum. • Example of conservation of Angular Momentum. • Simultaneous Rotation and Translational Motion
4. 4. © Copyright PCTI Limited 2012 Centre of Mass Of a Rigid Body .The potiential energies of particles 1 and 2 are and respectively.The potential energy of the particle at C is 2mgz. • The point C is called the centre of mass (CM) of the system. .
5. 5. © Copyright PCTI Limited 2012 Definition of CM • Some forces can be due to sources outside the body. These forces are called the external forces.Some other forces arise due to the interaction among the particles of the body. These are called internal forces. • In the case of a rigid body, the sum of the internal forces is zero because they cancel each other in pairs. • The CM of a body moves as though the entire mass of the body were located at that point and it was acted upon by the sum of all the external forces acting on the body.
8. 8. © Copyright PCTI Limited 2012 Moment Of Inertia The moment of Inertia must be specified with respect to a chosen axis of rotation.For a point mass the moment of inertia is just the mass times the square of perpendicular distance of the rotational axis.
9. 9. © Copyright PCTI Limited 2012 Moment of Inertia of Uniform Bodies
10. 10. © Copyright PCTI Limited 2012 Memory Map Of Moment of Inertia
11. 11. © Copyright PCTI Limited 2012 Theorem Of Parallel Axis • The moment of inertia about an axis parallel to the axis passing through its centre of mass is equal to the moment of inertia about its centre of mass plus the product of mass and square of the perpendicular distance between the parallel axes
12. 12. © Copyright PCTI Limited 2012 Theorem of perpendicular axes • The sum of the moments of inertia about x and y axes is equal to the moment of inertia about the z–axis.
13. 13. © Copyright PCTI Limited 2012 Torque and Couple • A couple is two equal forces which act on two opposite direction on an object but not from the same point so have a turning effect. • Torque is calculated by the product of either of forces forming the couple and the arm of couple.