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3 years ago

If one's hands are being warmed by holding them to one side of a flame, the predominant form of heat transfer is what process?

Physics

1 answer:

avanturin [10]3 years ago

4 0

Answer:

b. radiation

Explanation:

The correct choice is

b. radiation

Radiation is the process of heat transfer where no medium is required. Air is present between hands and flame and thermal conductivity of air is very low.

The hands are not in direct contact with the flame, hence conduction process of heat transfer is not possible.

In convection process of heat transfer, we have the warmer part of the medium moving towards the colder part. hence the convection is also not responsible for transfer of heat in this scenario

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A steel guitar string with a diameter of 0.300 mm and a length of 70.0 cm is stretched by 0.500 mm while being tuned. How much f

Ganezh [65]

Answer:

10.1 N

Explanation:

Your answer is 10.1 N, I don't actually know how to do it but I hope it helps.

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2 years ago

A football is kicked from the ground with a velocity of 38m/s at an angle of 40 degrees and eventually lands at the same height.

Anastasy [175]

Initially, the velocity vector is $\langle 38cos(40^{\circ}),38sin(40^{\circ}) \rangle=\langle 29.110, 24.426 \rangle$ . At the same height, the x-value of the vector will be the same, and the y-value will be opposite (assuming no air resistance). Assuming perfect reflection off the ground, the velocity vector is the same. After 0.2 seconds at 9.8 seconds, the y-value has decreased by $4.9(0.2)^2$ , so the velocity is $\langle 29.110, 24.426-0.196 \rangle = \langle 29.110, 24.23 \rangle$ .

Converting back to direction and magnitude, we get $\langle r,\theta \rangle=\langle \sqrt{29.11^2+24.23^2},tan^{-1}(\frac{29.11}{24.23}) \rangle = \langle 37.87,50.2^{\circ}\rangle$

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2 years ago

Which type of macromolecules a cell brake down food?

kobusy [5.1K]

Answer:

Hope this helps you find the answer

Explanation:

The proteins, lipids, and polysaccharides that make up most of the food we eat must be broken down into smaller molecules before our cells can use them—either as a source of energy or as building blocks for other molecules.

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2 years ago

Why does of beam of light ben when it passes into a new medium?

Pachacha [2.7K]

Answer:

The bending occurs because light travels more slowly in a denser medium.

3 0

2 years ago

When will an object dropped from rest attain a speed of 30 m/s?

stich3 [128]

<h3><u>Answer</u> :</h3>

Initial velocity = zero (i.e., free fall)

Final velocity = 30m/s

Acceleration due to gravity = 10m/s²

For a body falling freely under the action of gravity, g is taken positive $.$

◈ <u>First equation of kinenatics</u> :

⇒ v = u + gt

⇒ 30 = 0 + 10t

⇒ t = 30/10

⇒ <u>t = 3s</u>

Hence, object will attain a speed of 30m/s after 3s.

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3 years ago