Consevation of energy question

a pendulum has 15J of PE at the top of its swing
a) What is the KE at the bottom of the swing
b)At another time the pendulum has 8J of PE. What is its kinetic energy?
c)For the pendulum in "b", what will its kinetic energy be if it loses 2J to heat?

Recall that, at all times,
total mechanical energy, ME = PE + KE.

At the top of its swing, its PE = 15J, so this is the max mechanical energy that it can have.

a) At the bottom of the swing, all of its PE has been converted to KE so KE = 15 J

b) ME = PE + KE
15 = 8 + KE
KE = 15 - 8 = 7 J

c) KE(new) = KE(old) - 2 = 7 - 2 = 5J

a) 15 J
b) 7 J
c) 5 J