Question

The gravitational potential difference between the surface of a planet and a point $20m$ above it is $16J/kg$. Then the work done in moving a $2kg$ mass by $8m$ on a slope $60$ degree from the horizontal, is:

• A. $11.1J$
• B. $5.5J$
• C. $16J$
• D. $27.7J$

Answer 1

The correct option is A $11.1J$

Let acceleration due to gravity in the planet is $g_p$

Then gravitational potential difference

=$g_{p}h$

$16=g_p\times 20$

$g_p=\frac{16}{20}=\frac{4}{5}m/s^2$

Workdone=$m{g}_{p}h=2\times \frac{4}{5}\times 8\times \sin 60$

$⟹11.09J$