8. What is the weight of an object at the centre of the earth?
Answers
Answer:
The "weight of an object" at earth centre of 'radius R' is zero. Explanation: The weight of an object is the force with that an object is attracted towards the earth centre. The weight (W) of a body is the "product of its mass" (m) and the "acceleration due to gravity"
Weight, by definition, is the 'Gravitational force' acting on body due to earth.
Now, the thing to note in this scenario is that the body is inside the earth. We cannot consider whole earth as a single entity attracting the body towards its centre in this case. Let's see why...
When the body is inside the earth, let's say some distance below the the surface level, the part of earth above it, is not attracting the body towards the centre of the earth anymore, but in the upward direction. The part of the earth below the body is the only part attracting it towards the centre, which has lesser mass than the whole earth. Hence, the gravitational force acting on body decreases with the depth.
If the body is at centre of the earth, all the mass of the earth is 'surrounding' the body; Each particle of earth attracting the body in respective direction (& not towards the centre). Since, the body is at the centre, the effective force on the body will be of magnitude zero. Hence, the weight of body at the centre of the earth is zero.
Follow me please
