A running man has the same kinetic energy as that of a boy of half his mass. The man speeds up by 2 ms^(-1) and the boy changes his speed by x m s^(-1) so that the kinetic energies of the boy and the man are again equal. Then x in m s^(-1) is

A running man has the same kinetic energy as that of a boy of half his

1.	A running man has the same kinetic energy as that of a boy of half his mass. The man speeds up by 2 ms^(-1) and the boy changes his speed by x m s^(-1) so that the kinetic energies of the boy and the man are again equal. Then x in m s^(-1) is
Answer» <html><body><p>1/2 <br/>`2sqrt(2)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/sqrt-1223129" style="font-weight:bold;" target="_blank" title="Click to know more about SQRT">SQRT</a>(2)`<br/>`2`</p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :Let the <a href="https://interviewquestions.tuteehub.com/tag/mass-1088425" style="font-weight:bold;" target="_blank" title="Click to know more about MASS">MASS</a> of man be m. <br/> Therefore, mass of the <a href="https://interviewquestions.tuteehub.com/tag/boy-903339" style="font-weight:bold;" target="_blank" title="Click to know more about BOY">BOY</a> is `m/2` <br/> As. `1/2 mv_1^2 = 1/2(m/2) v_2^2 :. v_1= (v_2)/(sqrt2)` <br/> `1/2 m(v_1 + 2)^2 = 1/2[m/2 (v_2 + <a href="https://interviewquestions.tuteehub.com/tag/x-746616" style="font-weight:bold;" target="_blank" title="Click to know more about X">X</a>)^2]` <br/> `:. (v_1 + 2)^2 = ((v_2 + x)^2)/(2) " or " v_1 + 2 = (v_2+ x)/(sqrt2)` <br/> But `v_1 = (v_2)/(sqrt2) :. x/(sqrt2) = 2 " or " x = 2sqrt(2)`.</body></html>