EXERCISE 4


2. Planetary scientists have found an impact crater off the
gulf coast of Mexico.  It apparently was created when a meteorite
struck Earth about 65 million years ago.

(a) This meteorite was travelling about 30 km/sec when it hit
Earth, and it was probably made of iron, which has a density of
7.9 g/cm^3.  Its size is estimated to be a sphere about 10 km across.
How much kinetic energy did it have when it hit Earth?

(b) Could this impact have wiped out the dinosaurs, as most scientists
currently believe?  Use numerical common sense, and outside sources as
appropriate, to arrive at your answer.