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5.Work, Energy, Power and Collision
easy
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 $
Solution
દરેક બોલ વડે મેળવાતો વેગ સમાન છે,
${v_1}\,\, = \,\,{v_2}\,\, = \,\,\sqrt {2gh} $
$\frac{{K.{E_1}}}{{K.{E_2}}}\,\, = \,\,\,\frac{{\frac{1}{2}\,\,{m_1}v_1^2}}{{\frac{1}{2}\,\,{m_2}v_2^2}}\,\, = \,\,\frac{{{m_1}}}{{{m_2}}}\,\, = \,\,\frac{2}{4}\,\, = \,\,\frac{1}{2}\,$
Standard 11
Physics
