Question

A ball of mass $2kg$ and another of mass $4kg$ are dropped together from a $60$ feet tall building. What will be the ratio of their kinetic energy after a fall of $30$ feet?

• A. $\sqrt{2}:1$
• B. $1:4$
• C. $1:2$
• D. $1:\sqrt{2}$

Answer 1

The correct option is C $1:2$

Both the bodies will have same velocity due to Galileo's law of falling bodies which states that all bodies fall at the same rate.

Therefore the ration of kinetic energies:

$\frac{\frac{1}{2}\times 2\times v^2}{\frac{1}{2}\times 4\times v^2}=\frac{1}{2}$