The mass of a sphereical planet is 5 times the mass of the earth, but its diameter is the same as that of the earth. How much work is done in lifting a stone of mass 3 kg through a distance of 1 m on the planet ? [g on the surface the earth `= 10 m//s^(2)`]

Options

A. 100 J
B. 150 J
C. 200 J
D. 50 J

Answer

B

Explanation

G on the surface of the earth is given by `g = (GM)/(R^(2))` and for the planet `g'=(GM')/(R'^(2))=G.(5M)/(R^(2))`
`therefore (g')/(g)=5 " " therefore g'=5g`
`therefore` Work done in lifting the stone, through a distance of 1 m is
`W = mg'h = 5 mgh = 5xx3xx10xx1=150 J`