Why is coal considered a nonrenewable resource? check all that apply.
1.coal is burned to generate electricity.
2.coal power plants give off large quantities of smoke and ash.
3.coal forms so slowly that we could use up the supply that exists now.
4.coal is available in limited amounts.

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.