"6.5 km/hr" is not a velocity. It's just a speed, so
we don't know what direction he's walking.
If he happens to be walking north, then it takes him
(12 km) / (6.5 km/hr) = 1.846... hours (rounded) .
If he's walking in any other direction, it takes him longer than that.
If the angle between north and the direction he's walking is
90 degrees or more, then he can never cover any northward
distance, no matter how long he walks.
Elastic Potential Energy because the elasticity in the string stores up the energy.
The answer is all of the above because an ecosystem is how organisms and their environment interact. Population is animals, niche is and organism, and the habitat is the environment.
