Answer:
3430000 J
Explanation:
The formula for potential energy is PE=mgh.
M being the mass, g being the force of gravity, and h being the height.
First thing you want to do is convert 250 kg to g (grams).
From there you get 25000g and you have to multiply that by 14m and 9.8m/s^2 (the force of gravity is constant, at least on earth).
Depending on the height of the building they can break due to impact on the floor.
B)
The speed of the cart changed because it stopped.
Hope I could help!
-Marshy
