Question

A 500kg pig is standing at the top of a muddy hill on a rainy day. the hill is 100.0m long with a vertical drop of 30.0m. the pig slips and begins to slidedown the hill. What is the pig's speed at the bottom of the hill? Use the Law of conservation of Energy.

Answer 1

Mechanical energy would not be cnserved in such a situation. You have to consider the frictional force associated with sliding in mud.

However, if you want the book's expected answer, use
V = sqrt(2gH)
where H is the height of the hill.

The pig's mass and the length of the slope do not matter.