Answer:
Length = 2.453 m
Explanation:
Given:
Resistivity of the wire (ρ) = 1 × 10⁻⁶ Ω-m
Diameter of the wire (d) = 0.250 mm = 0.250 × 10⁻³ m
Resistance of the wire (R) = 50 Ω
Length of the wire (L) = ?
The area of cross section is given as:

We know that, for a constant temperature, the resistance of a wire is directly proportional to its length and inversely proportional to its area of cross section. The constant of proportionality is called the resistivity of the wire. Therefore,

Expressing the above in terms of length 'L', we get:

Plug in the given values and solve for 'L'. This gives,

Therefore, length of No. 30 wire (of diameter 0.250 mm) is 2.453 m.
one disadvantage is that magnets the opposites attract so the same type of magnets like n+n will keep repelling unless you use the opposite side of the magnet the it will attract
Answer:
6957.04N
Explanation:
Using
vf2=vi2+2ad
But vf = 0 .
So convert 50km/hr to m/s, and you need to convert 61 cmto m
(50km/hr)*(1hr/3600s)*(1000m/km) = 13.9m/s
61cm * (1m/100cm) = .61m
So n
0 = (13.9m/s)^2 + 2a(.61m)
a = 158.11m/s^2
So
using F = ma
F = 44kg(158.11m/s^2) = 6957.04N
Answer:
86 turns
Explanation:
Parameters given:
Magnetic torque, τ = 1.7 * 10^(-2) Nm
Area of coil, A = 9 * 10^(-4) m²
Current in coil, I = 1.1 A
Magnetic field, B = 0.2 T
The magnetic toque is given mathematically as:
τ = N * I * A * B
Where N = number of turns
To find the number of turns, we make N subject of formula:
N = τ/(I * A * B)
Therefore:
N = (1.7 * 10^(-2)) / (1.1 * 9 * 10^(-4) * 0.2)
N = 85.85 = 86 turns (whole number)
The number of turns must be 86.