Two discs of same moment of inertia rotating about their regular axis passing through centre and perpendicular to the plane of the disc with angular velocities ω1 and ω2. They are brought into contact face to face coinciding the axis of rotation. The expression for loss of energy during this process is from Physics System of Particles and Rotational Motion Class 11 Manipur Board
Zigya Logo

Chapter Chosen

System of Particles and Rotational Motion

Book Chosen

Physics Part I

Subject Chosen

Physics

Book Store

Download books and chapters from book store.
Currently only available for.
CBSE Gujarat Board Haryana Board

Previous Year Papers

Download the PDF Question Papers Free for off line practice and view the Solutions online.
Currently only available for.
Class 10 Class 12

Two discs of same moment of inertia rotating about their regular axis passing through centre and perpendicular to the plane of the disc with angular velocities ω1 and ω2. They are brought into contact face to face coinciding the axis of rotation. The expression for loss of energy during this process is

  • 1 half straight I left parenthesis straight omega subscript 1 space plus straight omega subscript 2 right parenthesis squared
  • 1 fourth straight I left parenthesis straight omega subscript 1 space plus straight omega subscript 2 right parenthesis squared
  • straight I left parenthesis straight omega subscript 1 space plus straight omega subscript 2 right parenthesis squared
  • 1 over 8 straight I left parenthesis straight omega subscript 1 space plus straight omega subscript 2 right parenthesis squared

B.

1 fourth straight I left parenthesis straight omega subscript 1 space plus straight omega subscript 2 right parenthesis squared

C.

straight I left parenthesis straight omega subscript 1 space plus straight omega subscript 2 right parenthesis squared
increment KE space equals space 1 half fraction numerator straight I subscript 1 straight I subscript 2 over denominator 2 straight I subscript 1 plus space straight I subscript 2 end fraction space left parenthesis straight omega subscript 1 space minus straight omega subscript 2 right parenthesis squared
equals space 1 half fraction numerator straight I squared over denominator left parenthesis 2 straight I right parenthesis end fraction left parenthesis straight omega subscript 1 minus straight omega subscript 2 right parenthesis squared
space equals 1 fourth straight I left parenthesis straight omega subscript 1 minus straight omega subscript 2 right parenthesis squared
increment KE space equals space 1 half fraction numerator straight I subscript 1 straight I subscript 2 over denominator 2 straight I subscript 1 plus space straight I subscript 2 end fraction space left parenthesis straight omega subscript 1 space minus straight omega subscript 2 right parenthesis squared
equals space 1 half fraction numerator straight I squared over denominator left parenthesis 2 straight I right parenthesis end fraction left parenthesis straight omega subscript 1 minus straight omega subscript 2 right parenthesis squared
space equals 1 fourth straight I left parenthesis straight omega subscript 1 minus straight omega subscript 2 right parenthesis squared
1973 Views

What is the need of centre of mass?

Newton’s second law of motion is strictly applicable to point masses only. To apply the Newton's law of motion to rigid bodies, the concept of centre of mass is introduced.

The concept of centre of mass of a system enables us to discuss overall motion of the system by replacing the system by an equivalent single point object. 
911 Views

Define centre of mass.

Centre of mass of a body or a system of bodies is a point at which the entire mass of the body or system is supposed to be concentrated. 
1449 Views

Is it necessary for centre of mass to lie within the body?

No, centre of mass needs not to lie within the body. It is not necessary that the total mass of the system be actually present at the centre.

The position of the centre of mass is calculated using the usual Newtonian type of equations of motion. 
943 Views

What is the significance of defining the center of mass of a system?

The motion of n particle system can be reduced to one particle motion.

An equivalent single point object would enable us to discuss the overall motion of the system. 
794 Views

Is it necessary that there should be matter at the centre of mass of system?

No, it is not necessary that there be matter at the centre of mass of the system.

For e.g., if two equal point masses are separated by certain distance, the centre of mass lies at the mid point of two point masses and there is no mass at that point.
730 Views