A roller coaster of mass 1000.0 kg passes point A with a speed of 1.80 m/s?

Question

point a= 30m
point b= 0m
point c= 25m
point d= 12m
1. What is the total mechanical energy of the roller coaster at point A?
2. What is the speed of the roller coaster at point B?
3. What is the potential energy and the kinetic energy of the roller coaster at point C?
4. Derive an expression for the speed of the cart using the variables E, m, g, and h.
5. Determine the speed of the roller coaster at D.

Answer 1

reference potential energy to ground
U = m g h
Ke = (1/2) m v^2

1
E = U + Ke = 1000*9.8*30 + 500 (1.8)^2

2
E = 0 + Ke
so (1/2) m (Vat B)^2 = E from 1 above

3
same old E from part 1
E = 1000*9.8*25 + Ke at C

4
(1/2) m v^2 = E - m g h

5
(1/2) m v^2 = E - m g h

Answer 2

is damon answer right??