3. If John leaves his house to walk his dog and he walks around the block, what is

natita [175]

Short Answer

3: C

4: D

Problem Three

Remark

Somewhere we ought to be told that this is the Doppler Effect. I have never done a problem using this formula, so I think I'm doing it correctly, but no guarantees. My guess is that the frequency increases as it comes towards you and decreases as it moves away from you. I think that is correct.

Formula

Givens

f' = observed frequency
f = actual frequency
v = velocity of sound or light waves.
vo = velocity of observer (in both cases 0)
vs = velocity of source.

f' = (v + vo) * f / (v - vs)

Solution

v = 3*10^8 m/s
f' = 1.1 f
f = f
vo = 0 We are standing still while all this is going on.
vs = ???

f'/f = 1.1

1.1 = (3*10^8 + 0 ) / (3*10^8 - vs)

3.3*10^8 - 1.1*vs = 3*10^8

3.3*10^8 - 3*10^8= 1.1 vs

0.3 * 10^8 = 1.1 vs

2.73 * 10^7 = vs

The closest answer is 3.00 * 10^7 which is C

Problem Four

Here what is happening is that you are looking for the frequency resulting from a wave moving towards you at 1/2 the speed of sound. You are not moving.

Givens

v = v
vs = 1/2 v
f ' = ?
f = 1000 hz
vo =0

f' = v/(v - 1/2v) * 1000

f' = v/ (1/2 v) * 1000

f' = 2 * 1000

f' = 2000 which is D

4 0

4 years ago

An electromagnetic wave in vacuum has an electric field amplitude of 470 V/m. Calculate the amplitude of the corresponding magne

lapo4ka [179]

Answer:

Magnetic field, B = $B=1.56\times 10^{-6}\ T$

Explanation:

It is given that,

The amplitude of an electromagnetic wave, E = 470 V/m

We need to find the amplitude of the corresponding magnetic field. The relation between electric and magnetic field is :

$B=\dfrac{E}{c}$

Where

c is the speed of light

$B=\dfrac{470\ V/m}{3\times 10^8\ m/s}$

B = 0.00000156

$B=1.56\times 10^{-6}\ T$

So, the amplitude of the corresponding magnetic field is $1.56\times 10^{-6}\ T$ . Hence, this is the required solution.

6 0

4 years ago

You toss a coin into a wishing well full of i liquid denser than the coin what will happen to the coin

Ksju [112]

If the liquid is denser than the coin, then the coin will eventually
come to rest floating, with part of it above the surface of the liquid.

That's exactly the situation if you drop the coin into mercury.

Density of copper . . . 8.96 gm/cm³
iron . . . 7.87
zinc . . . 7.13
silver . . 10.5
nickel . . .8.91
lead . . . 11.4

Density of mercury . . . 13.53 gm/cm³ !

6 0

4 years ago

Use the table of electric force between objects in two different interactions to answer the question. Interaction Charge on Obje

forsale [732]

Answer:?that’s a lot

Explanation:

6 0

3 years ago

Urgent!!! 50 points to who answers this question in a clear and simple explanation :

lina2011 [118]

You only need to use the right two simple formulas:

Work = (force) x (distance)

-- A mass that weighs 500N is being pulled down by gravity with a force of 500N. (That's what "weighs" means.) If you want to lift it straight up against gravity, you have to lift with a force of 500N.

The WORK you do on the mass is (500N) x (height you raise it to).

Power = (work) / (time)

-- 4,000 watts = (500N x Height) / 20 seconds

From here, the rest is just algebra ... pulling the height out of this equation:

Multiply each side by (20 sec):

(500N x height) = (4,000 watts x 20 sec)

Divide each side by (500N):

Height = (4,000 watts x 20 sec) / (500N)

Height = (4,000 x 20 / 500) (watt x second / Newton)

(Remember that "watt-second" = "Joule",

and "Joule" = "Newton-meter".)

Height = 160 meters

4 0

3 years ago