Potential energy is defined by formula

here
m = mass
g = acceleration due to gravity
h = height
Now here two different stones are located at same height
while mass of stone A is twice that of stone B
so here we can say potential energy of A is

Similarly potential energy of B is

now if we take the ratio of two energy

so we can say potential energy of stone A is two times the potential energy of B
Answer:
1.95m/s
Explanation:
Please view the attached file for the detailed solution.
The following were the conversion factors used in order to express all quatities in SI units:

The answer would be 27,000 Joules because (1/2) m v^2 =30*900 which equals 27,000 J
Answer:
Reduce the friction at the surface
Explanation:
If you can reduce the friction between the load and the plane less effort will be required as you are not having to apply effort to overcome friction.