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Most Important Selected Qs for JEE AdvancedPhysicsGravitation

A particle is dropped from a height equal to the radius of the earth above the tunnel dug through the earth as shown in the figure. R : Radius of earth. M : Mass of earth.

Options

  1. AParticle will oscillate through the earth to a height R on both sides
  2. BParticle will execute simple harmonic motion
  3. CMotion of the particle is periodic
  4. DParticle passes the centre of earth with a speed = 2 GM R

Correct answer

D. Particle passes the centre of earth with a speed = 2 GM R

Step-by-step solution

From COE (A) is correct. The force outside the earth varies as inverse square of the distance. motion is not simple harmonic. However, from symmetry of motion, the motion will be periodic. (C) is correct. From COE aligned & 1 2 m v^2=- G M m 2 R - (- 3 G M m 2 R ) & v= 2 G M R aligned (A),(C) and (D) are correct.

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