Answer:
"The distance between crests is 3 cm."
Explanation:
If he writes down "The distance between crests is 3 cm."
That means he is describing the wavelength of a wave and not longitudinal wave. He ought to write something about " direction "
Longitudinal waves are waves in which the displacement of the medium is in the same direction as, or parallel to, the direction of propagation of the wave. While
Wavelength is the distance between the two successfully Crest or trough
it's how much it weighs and how much force is pushing on it like a egg if i drop it the weigh can cause it to break and how much force the gravity is pushing on it.
The frequency of the wave is 
Explanation:
The frequency, the wavelength and the speed of a wave are related by the following equation:

where
c is the speed of the wave
f is the frequency
is the wavelength
For the radio wave in this problem,


Therefore, the frequency is:

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Part (a): Magnetic dipole moment
Magnetic dipole moment = IA, I = Current, A = Area of the loop
Then,
Magnetic dipole moment = 2.6*π*0.15^2 = 0.184 Am^2
Part (b): Torque acting on the loop
T = IAB SinФ, where B = Magnetic field, Ф = Angle
Then,
T = Magnetic dipole moment*B*SinФ = 0.184*12*Sin 41 = 1.447 Nm
Answer:
<span>GPE=81000J or 81kJ</span>
Explanation
Potential Energy = mgh = 20 x 9.8 x ?
<span>To find H use one of the equation of motion </span>
<span>= [(90)^2 - 0 ] / 2(9.8) </span>
<span>Potential Energy = mgh = 20 x 9.8 x 8100 /2(9.8) = 81000 J</span>