State Work-Energy Theorem. A bullet of mass $20\text{ g}$ strikes a target at $100\text{ m/s}$ and penetrates $10\text{ cm}$. Find average retarding force.
2.
A spring of spring constant $k = 500\text{ N/m}$ is compressed by $x = 0.2\text{ m}$. Calculate work done in compressing it and potential energy stored.
Section B: Conservation of Energy & Vertical Circle
3.
A body of mass $m$ is tied to a string of length $L$ and whirled in a vertical circle. Find minimum velocity at bottom for completing circle ($v_{bottom} = \sqrt{5gL}$).
4.
If momentum of a body increases by $50\%$, find the percentage increase in its kinetic energy.
Section C: Collisions & Power
5.
An engine pumps $1000\text{ kg}$ of water to a height of $10\text{ m}$ in $20\text{ s}$. Calculate power delivered by engine in kilowatts.
6.
Derive expression for final velocities in 1D head-on elastic collision of two unequal masses $m_1$ and $m_2$.
