Both Ray and his wrestling partner have kinetic energy by virtue of them moving. Ray has a mass [tex]m=100kg[/tex] , velocity [tex]v=4m/s[/tex]. Ray's kinetic energy is calculated as follows,
[tex]KE=\frac{1}{2} mv^2=\frac{1}{2} \times 100kg\times (4m/s)^2=800 J.[/tex]
Bobby wishes to archive the same amount of kinetic energy as Ray. To find what his velocity should be, we have to solve for [tex]v[/tex] in the kinetic energy formula. For Bobby, [tex]KE=800J[/tex], mass [tex]m=50kg[/tex].
So,
[tex]KE=\frac{1}{2} mv^2\\=>800J=\frac{1}{2} \times 50v^2\\=>v^2=\frac{1600J}{50kg} \\\\=>v=\sqrt{\frac{1600J}{50kg}} =5.66m/s[/tex] .
This means for Bobby to have the same kinetic energy as Ray, he has to run at [tex]5.66m/s.[/tex]
