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Homework Statement
A father racing his son has half the kinetic energy of the son,who has half the mass of the father.The father speeds up by ##1.0\frac {m} {s}## and then has the same kinetic energy as the son.What are the original speeds of (a)the father and (b) the son
Homework Equations
##E_k=\frac 1 2 mv^2##
The Attempt at a Solution
[/B]##m_f=2m_s##
##2E_f=E_s##
İnital situation;
##2E_f= m_f(v_{f_0})^2=E_s=\frac 1 2 m_s(v_{s_0})^2##
so
##m_f=2m_s##
then we will obtain ##4(v_{f_0})^2=(v_{s_0})^2##
Final situation
##\frac 1 2 m_f(v_{f_0}+1)^2=\frac 1 2 m_s(v_{s_0})^2##
then I get ##v_{f_0}=1\frac {m} {s}## which book says its ##2.4\frac {m} {s}##
Where I am going wrong ? (My native language is not english so If made a mistake in understanding the question so sorry )
Thanks
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