A stone is dropped from a height $h$. It hits the ground with a certain momentum $p$. If the same stone is dropped from a height $100\%$ more than the previous height, the momentum when it hits the ground will change by

A balloon of gross weight $W$ is falling vertically downward with a constant acceleration $a\left(<g\right)$. The magnitude of the air resistance is

A $10 \mathrm{kg}$ wagon is pushed with a force of $7 \mathrm{N}$ for $1.5 \mathrm{s}$, then with a force of $5 \mathrm{N}$ for $1.7 \mathrm{s}$ and then with a force of $10 \mathrm{N}$ for $3 \mathrm{s}$ in the same direction. What is the change in velocity brought about?