If Calcium lost two electrons, it would have the same number of electrons as Argon which has 18 electrons.
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Weight = electric force
<span>mg = qE </span>
<span>6.64x10^-27 x 9.81 = (2 x 1.60x10^-19) E
</span>qE =mg,
<span>E = mg/q = 6.64•10^-27•9.8/2•1.6•10^-19 =2.03•10^-7 V/m</span>
To solve the problem it is necessary to apply conservation of the moment and conservation of energy.
By conservation of the moment we know that

Where
M=Heavier mass
V = Velocity of heavier mass
m = lighter mass
v = velocity of lighter mass
That equation in function of the velocity of heavier mass is

Also we have that 
On the other hand we have from law of conservation of energy that

Where,
W_f = Work made by friction
KE = Kinetic Force
Applying this equation in heavier object.






Here we can apply the law of conservation of energy for light mass, then

Replacing the value of 

Deleting constants,


Answer:
(a) The constants required describing the rod's density are B=2.6 and C=1.325.
(b) The mass of the road can be found using 
Explanation:
(a) Since the density variation is linear and the coordinate x begins at the low-density end of the rod, we have a density given by

recalling that the coordinate x is measured in centimeters.
(b) The mass of the rod can be found by having into account the density, which is x-dependent, and the volume differential for the rod:
,
hence, the mass of the rod is 126.6 g.