Answer: Resistance = 
The approximate diameter of a penny is, <em>d</em> = 20 mm
thickness of penny is, <em>L = </em> 1.5×
mm
The area of penny along circular face is,
= 3.14×
m²
The resistivity of copper is <em>ρ</em> = 1.72 x 10-8 Ωm.
Resistance,

<em>12,25 km/h</em>
<em>≈ 3,4 m/s </em>
<em>v = d/t</em>
<em>= 12250m/h</em>
<em>= 12,25km/h</em>
<em>or</em>
<em>v = d/t</em>
<em>= 12250m/h</em>
<em>1h = 60m×60s = 3600s</em>
<em>= 12250m/3600s</em>
<em>≈ 3,4 m/s </em>
Models show how the atoms in a compound are connected.
<span>As it is descended from a vertical height h,
The lost Potential Energy = Mgh
The gained Kenetic Energy = (1/2)Mv^2; The rotational KE = (1/2)Jw^2
The angular speed w = speed/ Radius = v/R
So Rotational KE = (1/2)Jw^2 = (1/2)J(v/R)^2; J is moment of inertia
Now Mgh = (1/2)Mv^2 + (1/2)J(v/R)^2 => 2gh/v^2 = 1 + (J/MR^2)
As v = (5gh/4)^1/2, (J/MR^2) = 2gh/v^2 - 1 => (J/MR^2) = (8gh/5gh) - 1
so (J/MR^2) = 3/5 and therefore J = (3/5)MR^2.</span>