Satellite Orbit and Angular Momentum – Rankers Physics

Planet and Satellite: Practice Problem & Solution

Assertion (A): Even when orbit of a satellite is elliptical, its plane of rotation passes through the centre of earth. Reason (R): According to law of conservation of angular momentum plane of rotation of satellite always remain same.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Planet and Satellite. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A): For any central force, the orbit is always planar and contains the center of force (Earth's center). So (A) is true.


Reason (R): Gravitational force is a central force, so net torque is zero. This implies conservation of angular momentum, \(\vec{L} = \vec{r} \times \vec{p}\), which means the orbital plane is fixed. So (R) is true. (R) correctly explains (A).

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