JEE Mains · Physics · STD 11 - 7. gravitation
The weight of a body at the surface of earth is \(18\,N\). The weight of the body at an altitude of \(3200\,km\) above the earth's surface is \(........\,N\) (given, radius of earth \(R _{ e }=6400\,km\) )
- A \(9.8\)
- B \(4.9\)
- C \(19.6\)
- D \(8\)
Answer & Solution
Correct Answer
(D) \(8\)
Step-by-step Solution
Detailed explanation
Acceleration due to gravity at height \(h\) \(g ^{\prime}=\frac{ g }{\left[1+\frac{ h }{ R }\right]^2}\) So weight at given height \(mg ^{\prime}=\frac{ mg }{\left[1+\frac{ h }{ R }\right]^2}=\frac{18}{\left[1+\frac{1}{2}\right]^2}=8\,N\)
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