Physics

Physics

Problem

An object of mass mm is taken from the Earth’s surface to a height hh such that h≪Rh \ll R, where RR is the Earth’s radius. (i) Using the approximate expression gh=g(1−2h/R)g_h = g\bigl(1 - 2h/R\bigr), derive an expression for the fractional change in the weight of the object. (ii) Hence obtain the percentage decrease in weight in terms of hh and RR. (iii) Calculate the height above the Earth’s surface at which the weight of the object decreases by 1%1\%. Take R=6.4×106 mR = 6.4 \times 10^{6}\,\text{m}. a. (i) Using the relation gh=g(1−2h/R)g_h = g\bigl(1 - 2h/R\bigr), derive an expression for the fractional change in the weight of the object. c. (iii) Calculate the height above the Earth’s surface at which the weight of the object decreases by 1%1\%, taking R=6.4×106 mR = 6.4 \times 10^{6}\,\text{m}.

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