12. About 66 million years ago, a small asteroid struck the north tip of the Yucatan Peninsula, near the present location of the Mayan village of Chicxulub. If it had a mass of 3.1 x 10" kg and a velocity of 4.5 x 10# m/s, calculate the kinetic energy. (It was enough to wipe out the dinosaurs, as well as 75% of all the animal life on earth. We can get an estimate of the energy from the size of the crater - about 110 miles in diameter -- and typical asteroid velocities and densities allow us to estimate the size of the asteroid: Manhattan Island.) (10 points)