The kinetic energy needed to project a body of mass $m$ from the earth surface to infinity is

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$^{-2}$

At which height above the surface of the earth of radius $R$, will the acceleration due to gravity decrease by $0.1\%$?