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10 days ago

9

In a house the temperature at the surface of a window is 28.9 °C. The temperature outside at the window surface is 7.89 °C. Heat

is lost through the window via conduction, and the heat lost per second has a certain value. The temperature outside begins to fall, while the conditions inside the house remain the same. As a result, the heat lost per second increases. What is the temperature in degrees Celsius at the outside window surface when the heat lost per second doubles?

1 answer:

Yuliya22 [1.1K]10 days ago

3 0

Answer:

-13.18°C

Explanation:

To solve this issue, we must examine the principles associated with the rate of thermal conduction.

This rate is defined by the equation

$\frac{Q}{t} = \frac{kA\Delta T}{d}$

Where,

Q = Amount of heat transferred

t = time

k = Thermal conductivity constant

A = Area of cross-section

$\Delta T =$ Temperature difference across the material

d = Material thickness

The scenario indicates a heat loss that is double the initial value, which means

$Q_2 = 2*Q_1$

Substituting values yields,

$kA\frac{\Delta T_m}{x} = 2*kA\frac{\Delta T}{x}$

$\frac{\Delta T}{x}=2*\frac{\Delta T}{x}$

$\frac{T_i-T_o}{x} = 2\frac{T_1-T_2}{x}$

$\frac{28.9-T_o}{x} = 2\frac{28.9-7.86}{x}$

Solving for $T_o$ ,

$T_o = -13.18$

Thus, when the heat lost per second is doubled, the temperature on the external surface of the window is -13.18°C.

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Answer:

Electric flux is calculated as $\phi=31562.63\ Nm^2/C$

Explanation:

We start with the given parameters:

The electric field impacting the circular surface is $E=(4000j+3000k)\ N/C$

Our objective is to ascertain the electric flux passing through a circular region with a radius of 1.83 m situated in the xy-plane. The area vector is oriented in the z direction. The formula for electric flux is expressed as:

$\phi=E{\cdot}A$

$\phi=(4000j+3000k){\cdot}Ak$

Applying properties of the dot product, we calculate the electric flux as:

$\phi=3000\times Ak$

$\phi=3000\times \pi (1.83)^2$

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Consequently, the electric flux for the circular area is $\phi=31562.63\ Nm^2/C$ . Thus, this represents the required answer.

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1 day ago

A vector A is added to B=6i-8j. The resultant vector is in the positive x direction and has a magnitude equal to A . What is the

Yuliya22 [1153]

The answer is letter d, 8.3.

Here’s a solution for the given problem:

We have:

B = 6i - 8j

Let A be unknown; we'll denote A as = mi + nj

The resultant A+B lies along the x-axis (which implies A+B = Ki + 0j, where K is yet to be determined,

and we also know the magnitude of A+B is equivalent to the magnitude of A,

therefore, mag(A+B)=K=sqrt(m^2+n^2), or K^2 = m^2+n^2.

Using vector addition, A+B becomes (m+6)i + (n-8)j.

Since we know A+B = Ki + 0j, we can establish that:

m + 6 = K

n - 8 = 0, which gives n=8.

Thus, K^2=m^2+n^2 means (m+6)^2 = m^2 +8^2

= m^2 + 12m + 36 = m^2 + 64

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m = 2.33333...

Consequently, the magnitude of A is sqrt[(2.333...)^2 + 8^2] = 8.3333.

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Two identical carts travel at the same speed toward each other, and then a collision occurs. The graphs show the momentum of eac

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Explanation:

The term 'collision' refers to the interaction between two objects. There are two distinct types of collisions: elastic and inelastic.

In this scenario, two identical carts are heading towards each other at the same speed, resulting in a collision. In an inelastic collision, the momentum is conserved before and after the incident, but kinetic energy is lost.

After the event, both objects combine and move together at a single velocity.

The graph representing a perfectly inelastic collision is attached, illustrating that both carts move together at the same speed afterward.

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7 days ago

A block of mass m, initially held at rest on a frictionless ramp a vertical distance H above the floor, slides down the ramp and

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Answer:

$\displaystyle W=-m.g.H$

Explanation:

Transformation of Energy

Also known as energy conversion, this refers to the process in which energy shifts from one type to another. In this context, three energy forms are involved. When the object is stationary at the ramp's peak, it possesses gravitational potential energy, calculated as

$U=m.g.H$

As the object descends the frictionless ramp, it converts all its potential energy into kinetic energy, represented as

$\displaystyle K=\frac{m.v^2}{2}$

Thus,

$K=m.g.H$

Ultimately, when the object encounters a rough surface, all energy converts to thermal energy. The work performed by the friction force corresponds to the alteration in kinetic energy, as all velocity is lost in this process:

$\displaystyle W=\Delta E=K_f-K=0-K=-\frac{m.v^2}{2}$

Given the kinetic energy equals the initial potential energy:

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The two sides of the DNA double helix are connected by pairs of bases (adenine, thymine, cytosine, and guanine). Because of the

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Answer:

Explanation:

An image of the bond resulting from the search is attached.

Consider the force directed towards thymine as negative.

For the O-H-N combination:

The resulting force from this combination is:

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In the case of the N-H-N combination:

The total force acting from this combination is:

$F'=F_{NN}-F_{HN}\\\\=\frac{Ke^2}{r^2}-\frac{Ke^2}{r'^2}\\\\=Ke^2(\frac{-1}{r^2}+\frac{1}{r'^2})\\\\=(9.0\times 10^9Nm^2/kg^2)(1.6\times 10^{-19}C)^2[\frac{1}{[0.300\times 10^{-9}m]^2}-\frac{1}{((0300-0..110)\times 10^{-9})m)^2}]\\\\=-3.822\times 10^{-9}N$

The force that thymine applies on adenine is:

$F_{net}=F+F'\\\\=-5.03354\times 10^{-9}N-3.822\times 10^{-9}N\\\\=-8.8558\times 10^{-9}N$

When rounded to three significant figures, the net force is $8.86\times 10^{-9}N$

b)

The negative value indicates that the force is attractive, as it is aimed towards thymi.

c)

The force acting on the electron due to the proton is:

$F=\frac{Ke^2}{r^2}\\\\=\frac{(9.0\times 10^9Nm^2/C^2)(1.6\times 10^{-9}C)^2}{(5.29\times 10^{-11}m)^2}\\\\=8.233\times 10^{-8}N$

Since the electron and proton carry opposite charges, the force on the electron points towards the proton.

d)

The ratio of the above forces is:

$\frac{F}{F_{net}}=\frac{8.233\times 10^{-8}N}{8.233\times 10^{-8}N}\\\\=9.3$

Therefore, the bonding strength of the electron in the hydrogen atom is 9.3 times greater than the bonding force between adenine and thymine molecules.

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3 days ago