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2 years ago

Help please i don’t know

Physics

1 answer:

Fantom [35]2 years ago

4 0

Answer:

Explanation:

Potential energy at the top of the slide

PE = mgh = 49(9.8)(3) = 1,440.6 J

Energy converted to work of friction

W = Fd = 35(10) = 350 J

Converted potential that becomes kinetic energy

1440.6 - 350 = 1090.6 J

KE = ½mv²

v = $\sqrt{2KE/m}$

v = $\sqrt{2(1090.6)/49}$

v = 6.671902...

v = 6.7 m/s

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The word photokinetic means “moving in response to light”. Why does this make sense based on the two main parts (morphemes) in t

Ira Lisetskai [31]

Explanation:

photo means light in latin

kinetic means to move

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3 years ago

Although 0 dB is often referred to as the lower threshold of human hearing, it is important to realize that the human ear is not

d1i1m1o1n [39]

Answer:

a) 3000 Hz;

b) 30 dB;

c) 1000 times.

Explanation:

a) From the human audiogram given on the figure below the black line represents the threshold for hearing the sound at each frequency. We see that the least intensity is necessary for the frequency of about 3000 Hz.

b) Using the same audiogram we see that we would need the sound of the intensity of about 30dB.

c) The least perceptible sound at 1000 Hz must be 0dB while at 100 Hz it is 30dB. These are logarithmic quantities. To transform them to the linear quantities we use the formula

$I(\text{in dB})=10\log\frac{I}{I_0(\text{at }1000\text{ Hz})},$

where $I_0(\text{at }1000\text{ Hz})$ is the hearing threshold at 1000 Hz.

Therefore we have the following

$0\text{ dB}=10\log\frac{I_1}{I_0(\text{at }1000\text{ Hz})}\quad 30\text{ dB}=10\log\frac{I_2}{I_0(\text{at }1000\text{ Hz})}$

$I_1$ is the threshold at 1000Hz and $I_2$ is the threshold at 100Hz.

By exponentiating we have

$10^0=\frac{I_1}{I_0(\text{at }1000\text{ Hz})},\quad 10^3=\frac{I_2}{I_0\text{at }1000\text{ Hz}}.$

Now dividing these two equations we get

$\frac{I_2}{I_1}=\frac{10^3}{10^0}=1000.$

Therefore, the least perceptible sound at 100Hz is 1000 times more intense than the least perceptible sound at 1000Hz.

Note: I got these values unisng the audiogram that is attached here. The one that you have might be slightly different and might yield different answers.

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3 years ago

Explain what causes a satellite to stay in orbit and what happens to gravity at large heights

arlik [135]

Answer:

They are orbiting earth.So they stay in orbit.

We know that gravity increases with height.

Explanation:

1st Question Explanation:

Earth's gravity still pull on them.
Gravity combines with the satellite's momentum from its launch into space.This Combination cause the satellite go into the orbit.

2nd Question Explanation:

Gravity is caused by the Earth's spinning
Gravity is notable bless on high mountains or tall buildings.

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3 years ago

what is gravitational potential of a motionless 20kg rock that is 100m above the surface of the earth

Art [367]

Gravitational Potential Energy = mgh.

Where m = mass in kg.
g = acceleration due to gravity = 9.81 m/s2.
h = height in metres.
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3 years ago

Jack D. Ripper flipped out after missing a Must-Do-It question for the third time on his Minds On Physics assignment. Outraged b

Marrrta [24]

Answer:

Explanation:

Let the velocity after the 4 gram pencil strikes is v .

kinetic energy of the combination = 1/2 m v²

= .5 x ( 4 + 221 ) x 10⁻³ x v² = work done by friction

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Let velocity of pencil before collision be V

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4 x V = 225 x 86.92

V = 4889.25 cm / s

= 48.9 m /s .

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3 years ago