What will be the weight of a box, mass 10Kg on the surface of a hypothetical planet having mass double of Earth and the radius is 3 times of Earth

           W ’= 21.78 kg

Explanation:

The expression for weight is

          W = m g

let's look for the acceleration of gravity with the universal law of gravitation

          F = G m M / r2

          F = m (G M / r2)

without comparing the two equations

          g’= G M / r2

in that case M = 2 Mo and r = 3 ro

where mo and ro are the mass and radius of the earth

         we substitute

         g ’= G 2Mo / (3r₀) 2

         G ’= 2/9 G Mo / r₀²

         g ’= 2/9 g

the weight of the body on this planet is

         W ’= m g’

          W ’= m 2/9 g

let's calculate

          W ’= 2/9 10 9.8

           W ’= 21.78 kg

most voltage drop calculators want the distance between the source and destination. then internally, they double it so both the source and return wires are calculated. but you need to know which distance the calculator uses so you're not half of what you should be or double what you should be.

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