Answer:
Explanation:
The velocity of a wave in a string is equal to:
v = √(T / (m/L))
where T is the tension and m/L is the mass per length.
To find the mass per length, we need to find the cross-sectional area of the thread.
A = πr² = π/4 d²
A = π (3.0×10⁻⁶ m)²
A = 2.83×10⁻¹¹ m²
So the mass per length is:
m/L = ρA
m/L = (1300 kg/m³) (2.83×10⁻¹¹ m²)
m/L = 3.68×10⁻⁸ kg/m
So the wave velocity is:
v = √(T / (m/L))
v = √(7.0×10⁻³ N / (3.68×10⁻⁸ kg/m))
v ≈ 440 m/s
The speed of sound in air at sea level is around 340 m/s. So the spider will feel the vibration in the thread before it hears the sound.
Answer:
Alpha = ω^2 R where R is radius of blade
g = w^2 r where r is distance from center
ω^2 R = 11.5 ω^2 r
R / r = 11.5 / 9.8 = 1.17
Or r = .852 R
Since the angular acceleration depends on both R and ω it seems that one can only get r as it depends on R
Answer:
The number of turns in the second coil is more than the coil 1.
Explanation:
The magnetic field lines are the imaginary path on which an isolated north pole moves if it is free to do so.
The tangent at any point to the magnetic field line, gives the direction of magnetic field at that point.
More be the crowd ness of magnetic field lines more is the strength of magnetic field.
Here the crowd ness of magnetic field lines is more in figure 2 , so the magnetic filed in figure 2 is more than 1. It shows that the number of turns in the second coil is more than the 1 and also the current in the coil 2 is more than 1 .
