Answer:
Stayed the same
Explanation:
Potential energy is a function of mass, gravity and height relative to a reference level. If we take as the reference level the soil, this is the level where the potential energy is zero. Since in problem it is mentioned that the track is flat, this means that there are no height changes with respect to the reference level, therefore we can say that the potential energy remains unchanged.
Ep = m*g*h
where:
m = mass [kg]
g = gravity [m/s^2]
h = elevation [m]
