Gravitational potential problem: What do the counter lines represent?

Question

Here is the link to the problem/map:
http://www.jburroughs.org/science/mschober/em2-potential/E2_ws3.pdf

I understand the rest but I need help with questions 1 and 2

Answer 1

1.
a. In terms of gravitational potential contour lines represent equipotential lines. Contour lines are loci of equal elevation, and PE = mgh.

b. D, C & A, B

c.
i. 9.8(100 - 0) = 980 m^2/s^2 (J/kg)
ii. 9.8(200 - 0) = 1960 m^2/s^2
iii. 9.8(100 - 100) = 0
iv. 9.8(100 - 200) = - 980 m^2/s^2

c. At point C the 100 m and 0 m contour lines are very nearly parallel, so the motion of a ball will be SE (perpendicular to the contour lines)

2.
a. Closely spaced contours indicate a high PE gradient. A test mass will accelerate rapidly.
b. Widely separated lines indicate a low gradient. A test mass will accelerate slowly.

Answer 2

The contour lines represent different elevations in the mountain... the higher the elevation.. the greater the gravitational potential energy.

The closer the contour lines are together... the greater the percent grade or slope.

Answer 3

Contour lines represent points of equal elevation. The spacing of the lines represents the rate of change of elevation, or slope. A ball will follow a path that crosses the contour lines at right angles.