Kinetic energy because there is motion (PE converting to KE). Potential energy is the amount of stored energy.
You could attach the pulley to a secure object on the top of the ramp, and crank the pulley to bring the wagon up said ramp into a loading bay perhaps, or a track.
Hope I helped.

Explanation:
Natural length of a spring is
. The spring is streched by
. The resultant energy of the spring is
.
The potential energy of an ideal spring with spring constant
and elongation
is given by
.
So, in the current problem, the natural length of the spring is not required to find the spring constant
.

∴ The spring constant of the spring = 
Answer:
At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels. ... Since most of the atmosphere's molecules are held close to the earth's surface by the force of gravity, air pressure decreases rapidly at first, then more slowly at higher levels.
Explanation: