Question

I will be so thankful if u answer correctly!!​

Answer 1

(C) 200 N

Step-by-step explanation:

The acceleration due to gravity on earth
`g_(E)` is given by

`g_(E) = G(M_(E))/(R_(E)^(2))`

where
`G` = universal gravitational constant

`\:\:\:\:\:\:\:\:\:\:\:\:M_(R)` = mass of the earth

`\:\:\:\:\:\:\:\:\:\:\:\:R_(E)` = radius of the earth

Planet Krypton has twice the mass of earth and 3 times the radius so its acceleration due to gravity
`g_(K)` is

`g_(K) = G(M_(K))/(R_(K)^(2))`

`\:\:\:\:\:\: = G((2M_(E)))/((3R_(E))^(2))`

`\:\:\:\:\;\:= ((2)/(9))G(M_(E))/(R_(E)^(2))`

or

`g_(K) = ((2)/(9))\:g_(E)`

If we multiply both sides by Superman's mass, we get his weights on both planets:

`mg_(K) = ((2)/(9))\:(mg_(E))`

`W_(K) = ((2)/(9))\:W_(E) = ((2)/(9))(900\:N)= 200\:N`