Question

-point A = 100m , point B = 50m, point C = 30m and point D = 0m
-mass is 2500 kg

Answer 1

find the kinetic energy , velocity, and mechanical energy for each point

Answer 2

I'm sorry, but your questions seems to be rather incomplete. What physical issue are you actually talking about?

Answer 3

if the energy is conserved since point A is its max, you can find the total energy by doing mgh and then when mgh at point D=0 because there is no height, the potential energy will all be converted to kinetic so then you can solve for v since you know the mass. :)

Answer 4

also the mechanical energy should be the same at each point :)

Answer 5

@Nikkysterr: You could've been at least stated that you're talking about a free falling object in the gravitational field and that the values at the points are given heights. Otherwise, strictly speaking, it's impossible to answer the question (all you can do is guessing, what you might have meant).
And now (if I guess about what your question is actually about), I think Mythias is right. Maybe you could add, that you can solve for the velocity v at every point (not only at D) using the difference of height until that point.