Theres some calculations in this problem that I just dont get...(adsbygoogle = window.adsbygoogle || []).push({});

Start with the equations for initial and final momenta and kinetic energies and derive the

theoretical equation for the ratio fo [tex]K_f[/tex] to [tex]K_i[/tex]

[tex]P_i=Mv_i[/tex]

[tex]P_f=(M+m)v_f[/tex]

[tex]K_i=1/2Mv_i^2[/tex]

[tex]K_f=1/2(M+m)V_f^2[/tex]

[tex]K_f/K_i=1/2(M+m)v_f^2/1/2Mv_i^2=M/(M+m)[/tex] this part I dont get. I only get

[tex](M+m)/M[/tex] and im assuming that [tex]v_f[/tex] and [tex]v_i[/tex]

cancel out...

I basically solved for [tex]M=P_i/v_i[/tex] and [tex](M+m)=P_f/v_f

[/tex]

I plug it in to kinetic energy equations and get [tex]K_f/K_i=P_f/P_i[/tex] I guess [tex]

v_f[/tex] and [tex]v_i[/tex] cancel out? Is this answer correct?

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# Kinetic energy and momentum

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