Question

A ball of mass $2$kg and another of mass $4$ kg are dropped together from a $60$ feet tall building. After a fall of $30$ feet each towards earth, their respective kinetic energies will be in the ratio of?

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

Answer 1

The correct option is C $1:2$

Given that Mass $m_1=2$,$m_2=4$

As both balls are falling through the same height therefore they possess the same velocity

$KE=0.5m{v}^2$

$KE\alpha m$......(v is constant)

$\frac{{KE}_1}{{KE}_2}=\frac{m_1}{m_2}=\frac{2}{4}=\frac{1}{2}$