2ω is the resistance of the second wire if the resistance of the first is 4ω if two wires have the same length, but the second has twice the diameter of the first.
R= 4ω.
R = ρl/A
2d=r
R2=2ω
Resistance is the capacity of a conductor to obstruct the passage of an electric current through it. It is controlled by the interaction of the applied voltage and the electric current passing through it.
Conductors have very little resistance, whereas insulators have a significant amount of resistance. The resistance increases as the current flow decreases. Resistance is influenced by the properties and dimensions of the material (area of cross section)
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100 meters divided by a speed of 12.5 meters a second equals 8 seconds.
The launch velocity of the marble launcher is 34.65 m/s
Given that the launch velocity of marble launcher, launches a 25g marble to a distance of 73 cm (0.73 m) and the marble roll up to 6.2 meters before stopping. The launch height is 20 cm (0.2 m).
The time for landing can be calculated by the second equation of motion formula:
h = ut +
g
Let u = 0
0.2 = 0×t +
× 9.8 × 
= 
= 0.04
t = 0.2s
Now, the launch velocity of the marble launcher can be calculated by:
Speed = Distance / Time
Speed = 
Speed = 
Speed = 34.65 m/s
Therefore, the launch velocity of the marble launcher is 34.65 m/s
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A. Neutrons.
If it were electrons, it would be an ion.
If it were protons, it wouldn't be the same element.