The depth at which the value of $g$ becomes $25\%$ of that at the surface of the earth. $($ Radius of the ;earth $=$ 6400km.$)$

The altitude at which the weight of a body is only $64\%$ of its weight on the surface of the earth is (Radius of the earth $6,400km$)

At what height over the earth's pole does the freefall acceleration decreases by 1% ?

পৃথিবীর ব্যাসার্ধ 6400 km, পৃথিবীর নিজ অক্ষের সাপেক্ষে আবর্তনকাল 24 ঘণ্টা। ভূপৃষ্ঠে অভিকর্ষীয় ত্বরণ-9.8ms$^{-2}$