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3 years ago

20 points please helppp me I’m begging u this is due soon please come on ????? Anyone

Physics

2 answers:

Slav-nsk [51]3 years ago

7 0

Answer:

Gases are element .We can change the state of matter by the process of melting,evaporation,sublimation,freezing,condensation.

Virty [35]3 years ago

3 0

Ice can be melted at 0 degrees celsius and become water, water can boil at 100 degrees celsius and become a gas (plz give me brainliest)

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Which of the following is the best reason that trees care important for overall air quality?

Marina86 [1]

Trees are important because oxygen

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3 years ago

Calculate a rate of cooling down of air from 80 C to 5C Show calculation. Give an answer in cubic meters per minute and cfm.

antoniya [11.8K]

Explanation:

Given that,

Rate of cooling of air

Initial temperature= 80°C

Final temperature = 5°C

We need to calculate

Using newton's law of cooling

$\dfrac{dT}{dt}=c(T-T_{0})$

$\dfrac{dT}{dt}=c(\dfrac{T_{1}+T_{2}}{2}-T_{0})$

Where, $dT=T_{1}-T_{2}$

Here, $T =\dfrac{T_{1}+T_{2}}{2}$

$T_{0}$ = 25°C (surrounding temperature)

dt = 1 minute

$\dfrac{dT}{dt}=c(\dfrac{T_{1}+T_{2}}{2}-T_{0})$

Put the value into the formula

$\dfrac{80-5}{1}=c(\dfrac{85}{2}-25)$

$c=\dfrac{75}{17.5}$

$c=4.285\ cubic\ meter/minute$

Hence, This is the required answer.

3 0

3 years ago

Calculate the resistance of an electric bulb which allows a 10 A current when connected to a 220 V power source

kodGreya [7K]

Resistance can be calculated by Ohm's law

As per ohm's law we will have

$V = i * R$

here we will have

voltage = 220 volts

current = 10 A

So by the above formula we will have

$220 = 10* R$

$R = 22 ohm$

So resistance of the bulb is 22 ohm.

4 0

3 years ago

What causes the angle of the sun’s rays to change during the year on Earth?

amm1812

The tilt of Earth's axis hope this helps

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3 years ago

A 20-kg sled is being pulled along the horizontal snow-covered ground by a horizontal force of 26 n. starting from rest, the sle

Vesna [10]

Good morning.

We calculate the acceleration with the <em>Torricelli equation</em>:

$\star\ \boxed{\mathsf{V^2 = V_0^2 + 2a\Delta S}}$

We see that:

$\begin{cases}\mathsf{V_0 = 0}\\\mathsf{V = 2.3 \ m/s}\\\mathsf{\Delta S = 8.9 \ m}\end{cases}$

Now:

$\mathsf{(2.3)^2 = 0^2 + 2a\cdot 8.9}\\ \\ \mathsf{5.29 = 17.8a}\\ \\ \bold{\mathsf{a = 0.3 \ m/s^2}}$

Now we can calculate the resultant force that makes that acceleration of 0.3 m/s² with the 2nd Law of Newton:

$\mathsf{F_r = m\cdot a}\\ \\ \mathsf{F_r = 20\cdot 0.3}\\ \\ \mathsf{F_r = 6 \ N}$

We have a force of 26 N → and a friction force F ←. Adding those vectors, he have a force 6 N →. Therefore:

26 - F = 6

F = 20 N

We have a friction force of 20 N. We calculate the kinect coefficient with the formula:

$\star \ \boxed{\mathsf{F = \mu_k N}}$

Since we are in a horizontal plane, we hava that N = P = mg = 200 N

Therefore:

$\mathsf{20 = \mu_k 200}\\ \\ \boxed{\boxed{\mathsf{\mu_k = 0.1}}}$

5 0

3 years ago