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3 years ago

g To decrease the intensity of the sound you are hearing from your speaker system by a factor of 36, you can

Physics

1 answer:

Vlada [557]3 years ago

3 0

Answer:

Increase the distance by a factor of 6.

Explanation:

The intensity at a distance r is given by :

$I=\dfrac{P}{4\pi r^2}$

Here,

P is power emitted

r is distance from source

It means that the intensity is inversely proportional to the distance from the source.

To decrease the intensity of the sound you are hearing from your speaker system by a factor of 36, we can increase the distance by a factor of 6. Hence, this is the required solution.

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A 62-kg person jumps from a window to a fire net 20.0 m directly below, which stretches the net 1.4 m. Assume that the net behav

gayaneshka [121]

Answer:

a) x = 0.098

b) x = 2.72 m

Explanation:

(a) To find the stretch of the fire net when the same person is lying in it, you can assume that the net is like a spring with constant spring k. It is necessary to find k.

When the person is falling down he acquires a kinetic energy K, this energy is equal to the elastic potential energy of the net when it is max stretched.

Then, you have:

$K=U\\\\\frac{1}{2}mv^2=\frac{1}{2}kx^2$ (1)

m: mass of the person = 62kg

k: spring constant = ?

v: velocity of the person just when he touches the fire net = ?

x: elongation of the fire net = 1.4 m

Before the calculation of the spring constant, you calculate the final velocity of the person by using the following formula:

$v^2=v_o^2+2gy$

vo: initial velocity = 0 m/s

g: gravitational acceleration = 9.8 m/s^2

y: height from the person jumps = 20.0m

$v=\sqrt{2gy}=\sqrt{2(9.8m/s^2)(20.0m)}=14\frac{m}{s}$

With this value you can find the spring constant k from the equation (1):

$mv^2=kx^2\\\\k=\frac{mv^2}{x^2}=\frac{(62kg)(14m/s)^2}{(1.4m)^2}=6200\frac{N}{m}$

When the person is lying on the fire net the weight of the person is equal to the elastic force of the fire net:

$W=F_e\\\\mg=kx$

you solve the last expression for x:

$x=\frac{mg}{k}=\frac{(62kg)(9.8m/s^2)}{6200N/m}=0.098m$

When the person is lying on the fire net the elongation of the fire net is 0.098m

b) To find how much would the net stretch, If the person jumps from 38 m, you first calculate the final velocity of the person again:

$v=\sqrt{2gy}=\sqrt{2(9.8m/s^2)(38m)}=27.29\frac{m}{s}$

Next, you calculate x from the equation (1):

$x=\sqrt{\frac{mv^2}{k}}=\sqrt{\frac{(62kg)(27.29m/s)^2}{6200N/m}}\\\\x=2.72m$

The net fire is stretched 2.72 m

5 0

3 years ago

How much work does the electric field do in moving a proton from a point with a potential of +145 v to a point where it is -55 v

Aleks04 [339]

The work done by the electric field in moving a charge is the negative of the potential energy difference between the two locations, which is the product between the magnitude of the charge q and the potential difference $\Delta V$ :
$W=-\Delta U=-q\Delta V=-q (V_f -V_i)$
The proton charge is $q=1.6 \cdot 10^{-19}C$ , and the two locations have potential of $V_i = +145 V$ and $V_f=-55 V$ , therefore the work is
$W=-(1.6 \cdot 10^{-19}C)(-55 V-(+145 V))=3.2 \cdot 10^{-17}J$

5 0

3 years ago

Which of the following statements is true?

Grace [21]

I would recommend <span>C)Organic compounds always contain carbon and hydrogen.</span>

3 0

3 years ago

a 40 kilogramstudent runs up a staircase to a floor that is 5.0 meters higher than her starting point in 7.0 seconds. the studen

Wittaler [7]

When she reaches the top, she has more potential energy than she had at the bottom.

   Potential energy = (mass) x (gravity) x (height)

   = (40 kg) x (9.8 m/s²) x (5 m)

   = 1,960 more joules .

   Power = (energy) / (time)

   = (1,960 joules) / (7 seconds)

   = 280 watts

(about 0.375 horsepower)

3 0

3 years ago

What is the direction of the current flowing through the wire—left or right? The current flows to the .

muminat

Answer:

right

Explanation:

Current flows from the positive (+ve) terminal of the battery to the negative (-ve). This is called conventional current flow.

Therefore, the electrons are negatively charged and want to get away from the Negative Terminal and go to the Positive Terminal, Hence the electrons move from left to right and current flows from right to left.

5 0

3 years ago

Read 2 more answers