A charged particle moving in a magnetic field experiences a force equal to:

Thus, the magnitude of the force that the proton experiences is given by:

The magnetic field is perpendicular to the proton's velocity, therefore, we have
. Replacing the given values, we obtain:

Answer:
c. Groundwater contamination at a fracking site
Explanation:
all others could be sources from tens of square kilometers of surface area.
Fracking is limited to within a short range of the well hole.
<u>Answer
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A. 1 and 2
<u>Explanation
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At point 1 we have the highest potential energy and the kinetic energy is zero.
At 2 the potential energy is minimum and the kinetic energy is maximum.
The law of conservation of energy says that energy cannot be created nor destroyed. So, the change in P.E = Change in K.E.
P.E = height × gravity × mass. The height referred here is the perpendicular height. Gravity and mass are constant in this case.
From the diagram it can be seen clearly that the vertical height from 2 to 1 is much greater than from 4 to 3.
This shows that the change in P.E is greater between 1 and 2 and so is kinetic energy.