An asteroid of mass 10 kg is moving towards a space station at 1ms-. It is proposed to stop it by firing a 1 MW laser at it. For how long must the laser be fired? You may assume that the surface of the asteroid is perfectly reflective, all photons are incident perpendicular to the surface of the asteroid, and a photon's momentum is related to its energy by p= E, where c = 3 108 ms- is the speed of light. A C D E 3 x 10's 3 x 10 s 3 x 10- s B 7.5 x 10s 1.5 x 105 s [2]