Answer:
The bohr's model is the primitive model for the hydrogen atom, comparatively to the atom of valence shell. And it is derived from the hydrogen atom of the first approximation by using the quantum mechanics.
Basically, the model state that the electron revolved around in circular orbit in atom around the central nucleus. And it can be fixed in the circular orbit at the set of discrete distance at the nucleus.
the study of how matter and energy interact
the study of the natural world around us
the study of human bodies and how they move
The most important measure is awhips
Answer:
No, the farmer is not able to move the mule.
Explanation:
Mass =100 kg
Force=F=800 N
The coefficient between the mule and the ground=

Static friction force,f=
Normal force=N=mg
Static friction force,f=
Using 
F<f
Static friction force is greater than applied force.
Therefore , the farmer is not able to move the mule.