Question

A comet is highly elliptical orbit around the Sun. The period of the comet's orbit is 90days. Some statements are given regarding the collision between the comet and the earth. Mark the correct statement. [Mass of the Sun$=2\times {10}^{30}$kg, mean distance between the earth and the Sun$=1.5\times {10}^{11}$m]

• A. collision is there
• B. collision is not possible
• C. collision may or may not be there
• D. Enough information is not given

Answer 1

The correct option is B collision is not possible

Let both revolves in concentric circular orbit around the Sun.

Using, Kepler's law, $T^2\propto R^3$

Thus, $\frac{T_s^2}{T_e^2}=\frac{R_s^3}{R_e^3}$

Given: $R_e=1.5\times {10}^{11}m{T}_s=90days{T}_e=365days$

$⟹R_s<R_e$ i-e, both revolves in different concentric orbits thus they will never collide.