Gravitational potential difference between a point on surface of planet and another point 10 m above is 4J/kg. Considering gravitational field to be uniform, how much work is done in moving a mass of 2kg from the surface to a point 5 m above the surface?

Options

A. 4 J
B. 5 J
C. 6 J
D. 7 J

Answer

A

Explanation

Gravitational field `g=- (Delta V)/(Delta x)=- ((-4)/10)=4/10` J/kg-m
Work done in moving a mass of 2 kg from the surface to a point 5 m above the surface,
`W=mgh=(2 kg) (4/10 J/("kg - m")) (5 m)=4 J`