We know that KE=9J and the Mass (m) = 1kg. The formula to find this is going to be our Kinetic Energy Equation. K=[tex] \frac{1}{2} [/tex]m[tex] v^{2} [/tex]. But we will rearrange it to find the veloctiy so it looks like this: v=[tex] \sqrt{\frac{2K}{m} } [/tex]. Then just plug in the variables and solve.
