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Question
A planet has mass 6.4 × 1024 kg and radius 3.4 × 106 m. Calculate the energy required to remove an object of mass 800 kg from the surface of the planet to infinity.
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Solution
Given: M = 6.4 × 1024 kg, R = 3.4 × 106 m, m = 800 kg
To find: Energy required to remove the object from the surface of planet to infinity = B.E.
Formula: B.E. = `"GMm"/"R"`
Calculation: We know that,
G = 6.67 × 10–11 N m2/kg2
From formula,
B.E. = `(6.67 xx 10^-11 xx 6.4 xx 10^24 xx 800)/(3.4 xx 10^6)`
∴ B.E. =`(6.67 xx 6.4 xx 8)/3.4 xx 10^9`
∴ B.E. = 100.44 × 109 J
Energy required to remove the object from the surface of the planet is 1.004 × 1011 J.
Notes
The Answer given in the textbook is incorrect.
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