Firstly, the speed is not given in SI units, this is modified by changing the units from km/h to m/s by the following relationship; 70km/h = (70000/3600)m/s. Once this is complete the equation for kinetic energy is used, KE=(mv^2)/2 where m is the mass of the body, v is the speed of the body and KE is the kinetic energy of the body. The values derived and given in the question are then substituted into the equation to obtain a maximum kinetic energy of 2.46x10^4 joules.