Why Does the Sun Shine? (E&M??) Coulombs Law including the 1 / r - - PowerPoint PPT Presentation

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Why Does the Sun Shine? (E&M??) Coulombs Law including the 1 / r - - PowerPoint PPT Presentation

Nov 03, 2022 192 likes •294 views

Why Does the Sun Shine? (E&M??) Coulombs Law including the 1 / r 2 dependence on the separation 1. Newtons Law of Universal Gravitation shares many attributes of r r r 2 r 2 between point particles. qQ F G = GmM 1 F

slide-1
SLIDE 1

Why Does the Sun Shine? (E&M??)

  • 1. Newton’s Law of Universal Gravitation shares many attributes of

Coulomb’s Law including the 1/r2 dependence on the separation between point particles.

  • FC =

1 4πǫ0 qQ

r2 ˆ r
  • FG = −GmM
r2

ˆ

r
  • 2. What is the gravitational energy of

a sphere of mass M and radius R? Our Sun has M = 1.991 × 1030 kg and R = 6.96 × 108 m.

  • 3. The Sun produces about 3.86 ×

1026 J/s. If the source of the Sun’s energy is the energy stored in the field, how long would it last?

W hy Does the Sun Shine? – p.1/9

slide-2
SLIDE 2

Assembling a Charge Distribution

Consider the charge distribution shown below. How much work has to done to create it from nothing?

q1 q2 q3 q4

W hy Does the Sun Shine? – p.2/9

slide-3
SLIDE 3

Assembling a Charge Distribution

Consider the charge distribution shown below. How much work has to done to create it from nothing?

q1 q4 q2 r 23 r 24 r 12 r 14 r 34 r 13 q3

W hy Does the Sun Shine? – p.3/9

slide-4
SLIDE 4

Assembling a Charge Distribution

Consider the charge distribution shown below. How much work has to done to create it from nothing?

q1 q2 r 12 q4 r 14 r 34 q3

W hy Does the Sun Shine? – p.4/9

slide-5
SLIDE 5

Assembling a Charge Distribution

Consider the charge distribution shown below. How much work has to done to create it from nothing?

q1 q2 r 12 r 23 r 13 q4 r 14 r 34 q3

W hy Does the Sun Shine? – p.5/9

slide-6
SLIDE 6

Assembling a Charge Distribution

Consider the charge distribution shown below. How much work has to done to create it from nothing?

q

1

q2 q3 r12 r23 r13 r14 r 34 r24 q4

W hy Does the Sun Shine? – p.6/9

slide-7
SLIDE 7

Energy of a Charge Distribution

What is the energy stored in a uniformly charged solid sphere of radius R and charge Q? Use

W = ǫ0 2

  • V

E2dτ +

  • S

V E · d A

  • to calculate the energy.

x y z

W hy Does the Sun Shine? – p.7/9

slide-8
SLIDE 8

Energy of a Charge Distribution

W hy Does the Sun Shine? – p.8/9

slide-9
SLIDE 9

Why Does the Sun Shine? (E&M??)

  • 1. Newton’s Law of Universal Gravitation shares many attributes of

Coulomb’s Law including the 1/r2 dependence on the separation between point particles.

  • FC =

1 4πǫ0 qQ

r2 ˆ r
  • FG = −GmM
r2

ˆ

r
  • 2. What is the gravitational energy of

a sphere of mass M and radius R? Our Sun has M = 1.991 × 1030 kg and R = 6.96 × 108 m.

  • 3. The Sun produces about 3.86 ×

1026 J/s. If the source of the Sun’s energy is the energy stored in the field, how long would it last?

W hy Does the Sun Shine? – p.9/9