In the united states, most of our energy comes from this non–renewable resource, which has a negative effect on the environment. coal nuclear natural gas petroleum #ned answer asap!

In a system, when potential energy decreases, then entropy also decreases. true false

(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)

Where do magnetic lines of force enter earth?