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kumpel [21]
3 years ago
8

What causes sounds that are lower than 0 decibels?

Physics
1 answer:
vichka [17]3 years ago
4 0

Answer:

So 0 dB does not mean no sound, it means a sound level where the sound pressure is equal to that of the reference level. This is a small pressure, but not zero. It is also possible to have negative sound levels: - 20 dB would mean a sound with pressure 10 times smaller than the reference pressure, i.e. 2 μPa.

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A 50-g chunk of 80 degrees C iron is dropped into a cavity in a very large block of ice at 0 degrees C. Show that 5.5 g of ice w
Alenkasestr [34]

Answer:

5.5g of ice melts when a 50g chunk of iron at 80°C is dropped into a cavity

Explanation:

The concept to solve this problem is given by Energy Transferred, the equation is given by,

Q = mc\Delta T

Where,

Q= Energy transferred

m = mass of water

c = specific heat capacity

\Delta T = Temperature change (K or °C)

Replacing the values where mass is 50g and temperature is 80°C to 0°C we have,

Q = mc\Delta T

Q = 50*0.11*(80-0)

Q = 440cal

Then we can calculate the heat absorbed by m grams of ice at 0°C, then

Q_2 = mL = 80*m

How Q_1=Q_2, so

80m=440

m=\frac{440}{80}

m = 5.5g

Then 5.5g of ice melts when a 50g chunk of iron at 80°C is dropped into a cavity

7 0
4 years ago
Barney walks at a velocity of 1.7 meters/second on an inclined plane, which has an angle of 18.5° with the ground. What is the h
Viktor [21]
The velocities and the speed build a triangle, where the 1.7 m/s are the hypotenuse and the x-velocity and y-velocity are the other sides. 

<span>So the x-velocity is: speed*cos(angle) </span>

<span>now plug in </span>
<span>x=1.7 m/s * cos(18.5)=1.597 m/s </span>


3 0
3 years ago
if you have 34 pounds of meat at 200F and you immerse it in 15 liters of water at 25C what is the final temp of the water? ( spe
hram777 [196]

Answer:

The specific heat capacity is the heat or energy required to change one unit mass of a substance of a constant volume by 1 °C. The formula is Cv = Q / (ΔT ⨉ m)

5 0
3 years ago
How should scientists express very large numbers when reporting data ?
Ira Lisetskai [31]
To get the best possible answer. (sorry if im wrong)
7 0
3 years ago
Read 2 more answers
A circular coil of radius 5.0 cm and resistance 0.20 Ω is placed in a uniform magnetic field perpendicular to the plane of the c
Romashka [77]

Answer:

Explanation:

Given that,

Assume number of turn is

N= 1

Radius of coil is.

r = 5cm = 0.05m

Then, Area of the surface is given as

A = πr² = π × 0.05²

A = 7.85 × 10^-3 m²

Resistance of

R = 0.20 Ω

The magnetic field is a function of time

B = 0.50exp(-20t) T

Magnitude of induce current at

t = 2s

We need to find the induced emf

This induced voltage, ε can be quantified by:

ε = −NdΦ/dt

Φ = BAcosθ, but θ = 90°, they are perpendicular

So, Φ = BA

ε = −NdΦ/dt = −N d(BA) / dt

A is a constant

ε = −NA dB/dt

Then, B = 0.50exp(-20t)

So, dB/dt = 0.5 × -20 exp(-20t)

dB/dt = -10exp(-20t)

So,

ε = −NA dB/dt

ε = −NA × -10exp(-20t)

ε = 10 × NA exp(-20t)

Now from ohms law, ε = iR

So, I = ε / R

I = 10 × NA exp(-20t) / R

Substituting the values given

I = 10×1× 7.85 ×10^-3×exp(-20×2)/0.2

I = 1.67 × 10^-18 A

6 0
3 years ago
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