Question

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

Answer 1

Here, `h = 20 m`, Gravitational Pot. Diff. `= 16 J//kg`
the vertical distance through which the body has to be raised is `= 8 sin 60^(@) = 8 xx (sqrt(3//2)) = 4 sqrt(3) m`
Since gravitational pol. dff. For a distance of `20 m` is `16 J//kg`. Hence, the pot. diff. for a distance of
`4sqrt(3)m` for a body of mass `4 kg` is `= ((16)/(20) xx 4 sqrt(3)) J//kg`
Work done in lifting a `4 kg` body through a vertical height `4 sqrt(3)m` is
= gravitational pol.diff. `xx` mass `= ((16)/(20) xx 4sqrt(3)) xx 4 (6.4 xx 1.732)/(5) = 22.16 J`