1) Horizontal velocity, Vx
Vx is constant and equal to 5.0 m/s
The graph Vx(t) = 5.0 m/s is a horizontal line (parallel to the horizontal t-axis). that intercepts the vertical-axis at 5.0 and runs from t = 0 to t = 2.
2) Vertical velocity, Vy
Vy = gt = 10t
d = at^2 / 2 => tmax = √(2d / a) = √(2*20m/10m/s^2) = 2 s
Graph Vy is an inclined line with slope 10 m/s^2, that runs from t =0 to t = 2 s, and passes through the points (0,0), (1,10), and (2,20).
Thermal energy also known as 'heat energy' is a form of kinetic energy.
Not sure the precise concept of "normal observation", but I assume that is observed by "eyes".
Eye observation is basically macroscopic, but when you use a mark, which can be regarded as a point of mass, then it goes to microscopic.
Mark is a reference point which you can compare the relative position change, but with your eyes, first you cannot notice microscopic changes, second the eyes cannot precisely set a stable reference point.
