Suppose you are on a concrete surface and suddenly slip as you step on a patch
of ice. How do the pairs of action and
reaction forces differ when you are on
the dry walk and when you step on the
ice?

The answer is  the potential energy of the bob at position b is 1.47 joules.if the maximum height of the bob is 0.45 meters when it swings back,1.323   joules of energy was transformed to thermal energy.hope this