What is the relation between '$g$' and '$G$'?

Why does a spanner have a long handle?

If an angel visits an asteroid called $\mathrm{B} 612$ which has a radius of $20 \mathrm{m}$ and mass of $104 \mathrm{kg}$, what will be the acceleration due to gravity in $\mathrm{B} 612$ ?

State law of conservation of momentum and prove it.

Two similar trucks are moving with the same velocity on a road. One of them is loaded while the other is empty. Which of the two will require a larger force to stop it?

What is the relation between '$g$' and '$G$'?