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3 years ago

Which two statements are true of electromagnetic waves?

Physics

1 answer:

Usimov [2.4K]3 years ago

3 0

Answer:

B and C

Explanation:

Because EMWs are varying magnetic and electric radiation traveling at 90° to each other propagating energy form one place to another through vibration of these magnetic and electric fields

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Edit question A 37-cm-long wire of linear density 18 g/m vibrating at its second mode, excites the third vibrational mode of a t

Pachacha [2.7K]

Answer:

176.9N

Explanation:

The following data were given

wire length,L=37cm=0.37m

linear density=18g/m

tube length,=192cm=1.92m,

speed of sound,v=343m/s

Since it is an open-closed tube, the second harmonic frequency is expressed as

$f_{3}=3(\frac{v}{4l} )\\f_{3}=3(\frac{343}{4*1.92})\\f_{3}=133.98Hz$

The relationship between the tension, linear density and second harmonic frequency is expressed as

$f_{3}=\frac{1}{2l_{w}}\sqrt{\frac{T}{\alpha } } \\T=(f_{3}*2l_{w})^{2}\alpha \\T=(133.984*2*0.37)^{2}*18*10^{-3}\\T=176.9N$

7 0

4 years ago

A bullet with a mass of 4.26 g and a speed of 881 m/s penetrates a tree horizontally to a depth of 4.44 cm. Assume that a consta

sveta [45]

Let F be the magnitude of the frictional force. This force performs an amount of work W on the bullet such that

W = -Fx

where x is the distance over which F is acting. This is the only force acting on the bullet as it penetrates the tree. The work-energy theorem says the total work performed on a body is equal to the change in that body's kinetic energy, so we have

W = ∆K

-Fx = 0 - 1/2 mv²

where m is the body's mass and v is its speed.

Solve for F and plug in the given information:

F = mv²/(2x)

F = (0.00426 kg) (881 m/s)² / (2 (0.0444 m))

F = 37,234.8 N ≈ 37.2 kN

8 0

2 years ago

A transverse wave on a rope is given by y(x,t)= (0.750cm)cos(π[(0.400cm−1)x+(250s−1)t]). part a part complete find the amplitude

Pani-rosa [81]

The amplitude of a wave corresponds to its maximum oscillation of the wave itself.
In our problem, the equation of the wave is
$y(x,t)= (0.750cm)cos(\pi [(0.400cm-1)x+(250s-1)t])$
We can see that the maximum value of y(x,t) is reached when the cosine is equal to 1. When this condition occurs,
$y(x,t)=0.750 cm$
and therefore this value corresponds to the amplitude of the wave.

4 0

3 years ago

Read 2 more answers

At a height of ten meters above the surface of a freshwater lake, a sound pulse is generated. The echo from the bottom of the la

konstantin123 [22]

Answer:

Explanation:

Velocity of sound in air at 20 degree = 343 m/s

Velocity of sound in water at 20 degree = 1470 m/s

Time taken in to and fro movement in air

=( 2 x 10) / 343 = 0.0583 s

Rest of the time is

.171 - .0583 = .1127 s

This time is taken to cover distance in water. If d be the depth of lake

2d / velocity = time taken

2 d / 1470 = .1127

d = 82.83 m

5 0

3 years ago

Trong mặt phẳng Oxy, chất điểm chuyển động với phương trình<br><br> Tìm quĩ đạo của chất điểm.

QveST [7]

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6 0

3 years ago