Classical Mechanics
# Kinetic Energy

A $14\text{ kg}$ object initially at rest starts to fall freely. If air resistance is negligible, what is the object's kinetic energy after $0.5$ seconds?

The gravitational acceleration is $g=10\text{ m/s}^2.$

What is the kinetic energy of a $6\text{ kg}$ object moving at $10\text{ m/s}?$

A $10\text{ kg}$ object, $A$, travels at $6\text{ m/s},$ and a $6\text{ kg}$ object, $B$, travels at $10\text{ m/s}.$

Find the ratio $\text{K.E.}_A/\text{K.E.}_B$.

Recently, a meteor impacted Russia. The estimate of the meteor's size was $10~\mbox{tons}$ and it was estimated to have entered the earth's atmosphere at a speed of $14,600~\mbox{m/s}$. What was the total kinetic energy of such a meteor $\si{\joule}$ as it entered the atmosphere?

**Details and assumptions**

- One ton is $907~\mbox{kg}$.