The gravitational potential difference between the surface of a planet and a point 20 m above it is 16 J `kg^(-1)`. The work done in moving a 4 kg body by 8 m on a slope of `60^(@)` from the horizontal is

Options

A. 22.17 J
B. 2.217 J
C. 221.7 J
D. 0.2217 J

Answer

A

Explanation

`because" Gravitational force, " E=V/r`
Given, `E=16/20 Jkg^(-1)m^(-1)`
`because` Work done in moving a body,
`" "W=mEh`
`because " "h=8sin60^(@)=(8sqrt(3))/2=4sqrt(3)m`
Hence, work done in moving a 4 kg body by 8 m on a slope of `60^(@)` from the horizontal is
`" "W=4 times (16/20) times 4sqrt(3)=22.17J`