Two critical requirements must be met before light elements, like hydrogen or helium, will fuse and form heavier elements. the two requirements for nuclear fusion are
a) high energy and low density.
b) extreme temperatures and low density.
c) extremely high temperature and density.
d) strong gravitational forces and high density.

Which are advantages of renewable resources? check all that apply. renewable energy supplies are completely reliable everywhere. some renewable resources will never be used up. little or no waste is produced by renewable resource plants. electricity can be generated in large quantities. many renewable energy facilities have lower operating costs.

What is special about a dc circuit ?

3. a lunar exploration vehicle was created by a research team. it weighs 3,000 kg on the earth. it needs an acceleration of 10 m/s2 on the moon. in order to have the same acceleration, what will be the net force acting on the vehicle on the earth?