Answer:
Permanent magnetism (of the steel)
make me brainliestt :))
Answer:
Part(a): The frequency is
.
Part(b): The speed of the wave is
.
Explanation:
Given:
The distance between the crests of the wave,
.
The time required for the wave to laps against the pier, 
The distance between any two crests of a wave is known as the wavelength of the wave. So the wavelength of the wave is
.
Also, the time required for the wave for each laps is the time period of oscillation and it is given by
.
Part(a):
The relation between the frequency and time period is given by

Substituting the value of
in equation (1), we have

Part(b):
The relation between the velocity of a wave to its frequency is given by

Substituting the value of
and
in equation (2), we have

Explanation:
It is given that,
The horizontal and vertical component of velocity of an electron is:

The magnetic field acting there is given by :

(a) The magnitude of the magnetic force on the electron is given by :

q = e




(b) We know that the charge on proton is :

The magnetic force as same as for electron but the direction is opposite i.e.

Hence, this is the required solution.
Complete question:
The 100-kg homogeneous cylindrical disk is at rest when the force F =500N is applied to a cord wrapped around it, causing the disk to roll. Use the principle of work and energy to determine the angular velocity of the disk when it has turned one revolution (radius of the disk = 300mm).
Answer:
The angular velocity of the disk when it has turned one revolution is 16.712 rad/s
Explanation:
From the principle of work and energy;
U = E₂ - E₁, since the disk is initially at rest, T₁ = 0
U = E₂
Work done, U = product of force and perpendicular distance
U = F × d
As the cord winds, force act through the cord at a distance of 2d
U = F × 2d
Distance of one complete revolution = 2πR = 2π(0.3) = 0.6π
U = 500 × 2(0.6π) = 1885.2 J
Kinetic energy E₂ 
![E_2 = \frac{1}{2}[(\frac{1}{2}mR^2)\omega^2] + \frac{1}{2}m(\omega R)^2\\\\E_2 = \frac{1}{2}[(\frac{1}{2}*100*0.3^2)\omega^2] +\frac{1}{2}*100(\omega)^2*0.3^2\\\\E_2 = 2.25 \omega^2 +4.5 \omega^2\\\\E_2 = 6.75 \omega^2](https://tex.z-dn.net/?f=E_2%20%3D%20%5Cfrac%7B1%7D%7B2%7D%5B%28%5Cfrac%7B1%7D%7B2%7DmR%5E2%29%5Comega%5E2%5D%20%2B%20%5Cfrac%7B1%7D%7B2%7Dm%28%5Comega%20R%29%5E2%5C%5C%5C%5CE_2%20%3D%20%5Cfrac%7B1%7D%7B2%7D%5B%28%5Cfrac%7B1%7D%7B2%7D%2A100%2A0.3%5E2%29%5Comega%5E2%5D%20%2B%5Cfrac%7B1%7D%7B2%7D%2A100%28%5Comega%29%5E2%2A0.3%5E2%5C%5C%5C%5CE_2%20%3D%202.25%20%5Comega%5E2%20%2B4.5%20%5Comega%5E2%5C%5C%5C%5CE_2%20%3D%206.75%20%5Comega%5E2)
Recall that U = E₂
1885.2 = 6.75ω²
ω² = 1885.2/6.75
ω² = 279.2889
ω = √279.2889
ω = 16.712 rad/s
Therefore, the angular velocity of the disk when it has turned one revolution is 16.712 rad/s