Most of the energy of a supernova explosion is believed to come from the
conversion of gravitational potential energy, when a high mass star's
core collapses, into kinetic energy, heat, and other forms of energy.

(a) If 1.4 solar masses of matter collapsed from an average radius
of 10,000 km down to an average radius of 10 km, how much gravitational
potential energy would be converted into other forms?  Remember that
one solar mass is 2.0 * 10^30 kg.

(b) If the collapse described in Question 3(a) occurs over a period of
ten seconds, how many times more luminous is this supernova than the Sun?
Remember that the Sun's luminosity is 3.9 * 10^26 Watts.  By the way,
your answer should be very large.

(c) Approximately one percent of the energy released in Question 3(a)
comes out in the form of kinetic energy.  If that stellar core is
surrounded by approximately 10 solar masses of stellar matter, and
the kinetic energy is transferred to that matter, what would be the
average velocity of the stellar matter as it is blasted into space?
How fast would that debris travel a distance of 1 AU?