21.

One solid sphere A and another hollow sphere B are of same mass and same outer radii. Their moment of inertia about their diameters are respectively I_A and I_B such that


Where d_A and d_B are their densities.

• I_A = I_B

• I_A > I_B

• I_A < I_B

• I_A < I_B

What would be the work done in stretching a wire.

Spherical balls of radius R are falling in a viscous fluid of viscosity η with a velocity v. The retarding viscous force acting on the spherical ball is

• directly proportional to R but inversely proportional to v.

• directly proportional to both radius R and velocity v.

• inversely proportional to both radius R and velocity v.

• inversely proportional to both radius R and velocity v.

If two soap bubbles of different radii are connected by a tube,

• air flows from the bigger bubble to the smaller bubble till the sizes are interchanged.

• air flows from bigger bubble to the smaller bubble till the sizes are interchanged

• air flows from the smaller bubble to the bigger.

• air flows from the smaller bubble to the bigger.

The bob of a simple pendulum executes simple harmonic motion in water with a period t, while the period of oscillation of the bob is t0 in the air. Neglecting frictional force of water and given that the density of the bob is (4/3) x 1000 ms^-1 . What relationship between t and t0 is true?

• t = t₀

• t = t₀/2

• t = 2t₀

• t = 2t₀

A particle at the end of a spring executes simple harmonic motion with a period t₁, while the corresponding period for another spring is t₂. If the period of oscillation with the two springs in series is t, then

• T = t₁ + t₂

• 
• 
• 

The total energy of particle, executing simple harmonic motion is

• ∝ x

• ∝ x²

• independent of x

• independent of x

The displacement y of a particle in a medium can be expressed as y = 10⁻⁶ sin(110t + 20 x + π/4) m, where t is in seconds and x in a meter. The speed of the wave is

• 2000 m/s

• 5 m/s

• 20 m/s

• 20 m/s

A particle of mass m is attached to a spring (of spring constant k) and has a natural angular frequency ω₀. An external force F(t) proportional to cosωt (ω≠ω₀) is applied to the oscillator. The time displacement of the oscillator will be proportional to

In forced oscillation of a particle the amplitude is maximum for a frequency ω₁ of the force, while the energy is maximum for a frequency ω₂ of the force, then

• ω₁ = ω₂

• ω₁ > ω₂

• ω₁ < ω₂ when damping is small and ω₁ > ω₂ when damping is large

• ω₁ < ω₂ when damping is small and ω₁ > ω₂ when damping is large