My professor said that changes in E do work. In (a) the velocity and therefore the kinetic E of both twins stay the same, so you only look at the gain in gravitational potential energy (E = mgh). Therefore, to balance this identical gain in E, they must consume the same amount of E.
(b)...
Homework Statement
Two identical twins, A & B, are riding identical bikes up the same hill, both at constant speed. Twin A takes 20 seconds to climb the hill, while twin B takes 40 seconds.
a) Neglecting all forms of friction, which twin consumes more energy?
b) With friction, which twin...