Question

Calculate the value of 'g' (Chapter -Gravitation)

Answer 1

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we know that force ∝ 1/d^2

and force ∝ Mm/d^2

∴ force = G Mm/d^2 -------(i)

here G is the universal gravitation constant and it's value is 6.673 * 10^-11

we also know that force is the product of mass and acceleration, and there's always an acceleration in falling objects towards earth. that acceleration is represented as g.

∴ F = mg (∵ F = ma and g is the acceleration due to gravity) ------(ii)

by equation (i) and (ii), we get

⇒ mg = G Mm/d^2

⇒ g = G M/r^2 (the distance will be equal to the radius of earth)

putting values..

⇒ g = (6.7 * 10^-11 * 6 * 10^24)/(6.4 * 10^4)^2

⇒ g = 9.8ms^-2

here I took G = 6.7 as the approx value.

u can also take g = 10ms^-2 instead of 9.8ms^2 for easier calculation.

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