A positive charge Q2 is uniformly distributed over a nonconducting disc of radius a which has a concentric circular hole of radius b. At the center of the hole there is another nonconducting disc of radius d where a charge Q1 is uniformly distributed.
a) Find the surface charge density of the disc with the hole σ2.
b) Find the surface charge density 01 of the disc of radius d.
c) Find the total charge enclosed by the circle of radius

Answer:

a)    σ = [tex]\frac{Q_1}{ a^2 - b^2}[/tex] ,  b)  σ = [tex]\frac{Q_2}{d^2}[/tex] , c) Q_ {total} = Q₁ + Q₂,  σ_ {net} = [tex]\frac{Q_1 + Q_2}{\pi \ a^2}[/tex]

Explanation:

a) The very useful concept of charge density is defined by

          σ = Q / A

In this case we have a circular disk

The are of a circle is

         A = π r²

in this case we have a hole in the center of radius r = b, so

         A_net = π r² - π r_ {hollow} ²

         A_ {net} = π (a² - b²)

whereby the density is

          σ = [tex]\frac{Q_1}{ a^2 - b^2}[/tex]

b) The density of the other disk is

          σ = Q₂ / A₂

          σ = [tex]\frac{Q_2}{d^2}[/tex]

c) The total waxed load is requested by the larger circle

           Q_ {total} = Q₁ + Q₂

the net charge density, in the whole system is

          σ = [tex]\frac{Q_{total} }{ A_{total} }[/tex]

the area  is

          A_{total} = π a²

since the other circle is inside, we are ignoring the space between the two circles

          σ_ {net} = [tex]\frac{Q_1 + Q_2}{\pi \ a^2}[/tex]

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1. When an unbalanced force acts on an object,
O the object remains at rest
the weight of the object decreases.
O the object's motion changes.
the inertia of the object increases.

(a) What do you mean by rest?​

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Select the correct answer.
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A.
The framers didn’t want senators to worry about their constituents as often as representatives do.
B.
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C.
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D.
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help me pls
An object accelerates if it:

a.) changes the direction of its velocity but not the magnitude

b.)changes the magnitude of the velocity but not the direction

c.)changes its speed

d.) all of the above

e.) none of the above