Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Gravitation

Question:

A ball of mass m is dropped from a height h equal to the radius of the earth above the tunnel dug through the earth as shown in the figure. Choose the wrong options.

Options:

Particle will oscillate though the earth to a height h on both sides

Particle will execute simple harmonic motion 

Motion of the particle is periodic

Particle passes the centre of earth with a speed v = √(2GM/R)

Correct Answer:

Particle will execute simple harmonic motion 

Explanation:

Particle performs SHM inside tunnel but not outside surface, so, if just performs periodic motion with amplitude, (R + h) :

\(\frac{1}{2} mv^2 = \frac{3GMm}{2R} - \frac{GMm}{2R}\)

\(\frac{1}{2} mv^2 = \frac{GMm}{R}\)

\(\Rightarrow v = \sqrt{\frac{2GM}{R}}\)