Complete Question
A 10 gauge copper wire carries a current of 20 A. Assuming one free electron per copper atom, calculate the drift velocity of the electrons. (The cross-sectional area of a 10-gauge wire is 5.261 mm2.)
mm/s
Answer:
The drift velocity is 
Explanation:
From the question we are told that
The current on the copper is 
The cross-sectional area is
The number of copper atom in the wire is mathematically evaluated

Where
is the density of copper with a value 
is the Avogadro's number with a value 
Z is the molar mass of copper with a value 
So
Given the 1 atom is equivalent to 1 free electron then the number of free electron is

The current through the wire is mathematically represented as

substituting values

=> 
Answer:
The answer to your question is 1.35 Watts
Explanation:
Data
Work = W = 5 J
time = t = 3.7 s
Power = P = ?
Formula
Power is a rate in which work is done or energy is transferred over time
P = 
Substitution

Result
P = 1.35 W
Answer:
Magnitude of its angular momentum = 0.0017 kgm²/s
Explanation:
Angular momentum, L = Iω
I is mass moment of inertia and ω is angular velocity.
Phonograph is in disc shape,

Radius = 0.5 x 48 = 24 cm = 0.24 m
Angular velocity, ω = 3.2 rad/s
Mass, M = 18 g = 0.018 kg
Substituting

Magnitude of its angular momentum = 0.0017 kgm²/s
The force ffrom the ground that holds the rock up and prevents her from falling through the gound, unless the ground breaks.