Home
Class 11
PHYSICS
The moments of inertia of two rotating b...

The moments of inertia of two rotating bodies `A` and `B` are `I_A` and `I_B(I_A gt I_B)`. If their angular momenta are equal then.

A

a. Kinetic energy of A = Kinetic energy of B

B

b. Kinetic energy of A > Kinetic energy of B

C

c. Kinetic energy of A < Kinetic energy of B

D

d. Kinetic energy of the two bodies cannot be compared with the given data

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the relationship between the moments of inertia, angular momentum, and kinetic energy of the two rotating bodies A and B. ### Step-by-Step Solution: 1. **Understand the Given Information**: - We have two bodies, A and B. - Their moments of inertia are \( I_A \) and \( I_B \) respectively, with the condition \( I_A > I_B \). - Their angular momenta are equal, i.e., \( L_A = L_B \). 2. **Recall the Formula for Angular Momentum**: - The angular momentum \( L \) of a rotating body is given by the formula: \[ L = I \cdot \omega \] where \( I \) is the moment of inertia and \( \omega \) is the angular velocity. 3. **Set Up the Equations for Angular Momentum**: - For body A: \[ L_A = I_A \cdot \omega_A \] - For body B: \[ L_B = I_B \cdot \omega_B \] - Since \( L_A = L_B \), we can equate the two expressions: \[ I_A \cdot \omega_A = I_B \cdot \omega_B \] 4. **Express Angular Velocities in Terms of Each Other**: - Rearranging the equation gives: \[ \frac{\omega_A}{\omega_B} = \frac{I_B}{I_A} \] - Since \( I_A > I_B \), it follows that \( \frac{I_B}{I_A} < 1 \). Therefore, \( \omega_A < \omega_B \). 5. **Kinetic Energy of Each Body**: - The kinetic energy \( KE \) of a rotating body is given by: \[ KE = \frac{1}{2} I \omega^2 \] - For body A: \[ KE_A = \frac{1}{2} I_A \omega_A^2 \] - For body B: \[ KE_B = \frac{1}{2} I_B \omega_B^2 \] 6. **Relate Kinetic Energies Using Angular Velocities**: - Substitute \( \omega_A \) in terms of \( \omega_B \): \[ KE_A = \frac{1}{2} I_A \left(\frac{I_B}{I_A} \omega_B\right)^2 = \frac{1}{2} I_A \cdot \frac{I_B^2}{I_A^2} \cdot \omega_B^2 = \frac{I_B^2}{2 I_A} \cdot \omega_B^2 \] - Thus, we can compare \( KE_A \) and \( KE_B \): \[ KE_B = \frac{1}{2} I_B \omega_B^2 \] 7. **Compare the Kinetic Energies**: - Since \( I_A > I_B \) and \( \frac{I_B^2}{I_A} < I_B \) (because \( I_B < I_A \)), it follows that: \[ KE_B > KE_A \] ### Conclusion: From the above analysis, we conclude that the kinetic energy of body B is greater than that of body A. ### Final Answer: The kinetic energy of body B is greater than the kinetic energy of body A.

To solve the problem, we need to analyze the relationship between the moments of inertia, angular momentum, and kinetic energy of the two rotating bodies A and B. ### Step-by-Step Solution: 1. **Understand the Given Information**: - We have two bodies, A and B. - Their moments of inertia are \( I_A \) and \( I_B \) respectively, with the condition \( I_A > I_B \). - Their angular momenta are equal, i.e., \( L_A = L_B \). ...
Promotional Banner

Topper's Solved these Questions

  • SYSTEM OF PARTICLES AND ROTATIONAL MOTIONS

    NCERT FINGERTIPS ENGLISH|Exercise HOTS HIGHER ORDER THINKING SKILL|8 Videos
  • SYSTEM OF PARTICLES AND ROTATIONAL MOTIONS

    NCERT FINGERTIPS ENGLISH|Exercise NCER EXAMPLAR PROBLEMS|8 Videos
  • SYSTEM OF PARTICLES AND ROTATIONAL MOTIONS

    NCERT FINGERTIPS ENGLISH|Exercise ANGULAR MOMENTUM IN CASE OF ROTATIONS ABOUT A FIXED AXIS|16 Videos
  • PRACTICE PAPERS

    NCERT FINGERTIPS ENGLISH|Exercise All Questions|150 Videos
  • THERMAL PROPERTIES OF MATTER

    NCERT FINGERTIPS ENGLISH|Exercise Assertion And Reason|10 Videos

Similar Questions

Explore conceptually related problems

The moments of inertia of two rotating bodies A and B are l_(A) and I_(B) (I_(B) gt I_(A)) and their angular momentum are equal. Which one has a greater kinetic energy ?

Consider a uniform square plate shown in the figure. I_1 , I_2 , I_3 and I_4 are moment of inertia of the plate about the axes 1, 2, 3 and 4 respectively. Axes 1 and 2 are diagonals and 3 and 4 are lines passing through centre parallel to sides of the square. The moment of inertia of the plate about an axis passing through centre and perpendicular to the plane of the figure is equal to which of the followings. A. I_3 + I_4 B. I_1 + I_3 C. I_2 + I_3 D. 1/2 (I_1+I_2+I_3+I_4)

Two rotating bodies A and B of masses m and 2m with moments of inertia I_(A) and I_(B) (I_(B) gt I_(A)) have equal kinetic energy of rotation. If L_(A) and L_(B) be their angular momenta respectively, then

Two bodies have their moments of inertia I and 2 I respectively about their axis of rotation. If their kinetic energies of rotation are equal, their angular momenta will be in the ratio.

Two bodies have their moments of inertia I and 2I , respectively about their axis of rotation. If their kinetic energies of rotation are equal, their angular velocity will be in the ratio

Two circular discs A and B of equal masses and thicknesses. But are made of metals with densities d_A and d_B (d_A gt d_B) . If their moments of inertia about an axis passing through the centre and normal to the circular faces be I_A and I_B , then.

One solid sphere A and another hollow spher B are of same mass and same outer radii. Their moment of inertia aobut their diameters are respectively I_A and I_B such that where d_A and d_B are their densities,

The moment of inertia (I) and the angular momentum (L) are related by the expression

Two bodies with moment of inertia I_1 and I_2 (I_1 gt I_2) have equal angular momenta. If their kinetic energy of rotation are E_1 and E_2 respectively, then.

Let I_1 and I_2 be the moments of inertia of two bodies of identical geometrical shape, the first made of aluminum and the second of iron.