A proton is bombarded on a stationary lithium nucleus. As a result of the collision, two α -particles are produced. If the direction of motion of the α -particles with the initial direction of motion makes an angle cos−1(1/4) , find the kinetic energy of the striking proton. Given, binding energies per nucleon of Li7 and He4 are 5.60 and 7.06 MeV, respectively. (Assume mass of proton ≈ mass of neutron).