Q 1 :

A light hollow cube of side length 10 cm and mass 10 g, is floating in water. It is pushed down and released to execute simple harmonic oscillations. The time period of oscillations is yπ×102 s, where the value of y is (Acceleration due to gravity, g=10 m/s2, density of water =103 kg/m3)          [2025]

  • 2

     

  • 6

     

  • 4

     

  • 1

     

(1)

Additional buoyant force,

L2xρg=manet

anet=(L2ρgm)x

ω2=(L2ρgm)  ω=(L2ρgm)

T=2πmL2ρg

where m = 10 g, L = 10 cm, ρ = 1000 kg/m3

T=2π10×103(10×102)2×1000×10



Q 2 :

Assume that the earth is a solid sphere of uniform density and a tunnel is dug along its diameter throughout the earth. It is found that when a particle is released in this tunnel, it executes a simple harmonic motion. The mass of the particle is 100 g. The time period of the motion of the particle will be (approximately)

(take g = 10 ms-2, radius of earth = 6400 km)                    [2023]

  • 1 hour 24 minutes

     

  • 1 hour 40 minutes

     

  • 12 hours

     

  • 24 hours

     

(1)

T=2πRg=2π6400×10310

=2π×8×102=16π×102=5024 s=83.73 min

=1 hr 23.73 min

1 hr 24 min