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2 years ago

Why might people be able to walk barefoot on hot coals of wood without burning their feet?

Physics

2 answers:

ki77a [65]2 years ago

8 1

Hot coals of wood? Wood is not coals. So they can't burn their feet, there are no hot coals, just wood.

katovenus [111]2 years ago

8 0

The correct answer of this question is : Low thermal conductivity of hot coals.

EXPLANATION :

Before going to answer of this question, first we have to understand the nature of hot coals of wood in terms of conductivity.

The thermal conductivity of the wood is very small i.e it is thermally insulator.

Due to the less thermal conductivity of wood, the heat partially flows to the foot. The person will feel the heat, but not as much as the heat given by thermal conductors.

Hence, a barefoot person person can walk on hot coals of wood.

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A 1.4-kg cart is attached to a horizontal spring for which the spring constant is 50 N/m . The system is set in motion when the

marin [14]

Answer:

0.395 m

2.4 m/s

Explanation:

$m$ = mass of the cart = 1.4 kg

$k$ = spring constant of the spring = 50 Nm⁻¹

$x$ = initial position of spring from equilibrium position = 0.21 m

$v_{i}$ = initial speed of the cart = 2.0 ms⁻¹

$A$ = amplitude of the oscillation = ?

Using conservation of energy

Final spring energy = initial kinetic energy + initial spring energy

$(0.5) kA^{2} = (0.5) m v_{i}^{2} + (0.5) k x_{i}^{2} \\kA^{2} = m v_{i}^{2} + k x_{i}^{2} \\(50) A^{2} = (1.4) (2.0)^{2} + (50) (0.21)^{2} \\A = 0.395 m$

$m$ = mass of the cart = 1.4 kg

$k$ = spring constant of the spring = 50 Nm⁻¹

$A$ = amplitude of the oscillation = 0.395 m

$v_{o}$ = maximum speed at the equilibrium position

Using conservation of energy

Kinetic energy at equilibrium position = maximum spring potential energy at extreme stretch of the spring

$(0.5) m v_{o}^{2} = (0.5) kA^{2}\\m v_{o}^{2} = kA^{2}\\(1.4) v_{o}^{2} = (50) (0.395)^{2}\\v_{o} = 2.4 ms^{-1}$

5 0

3 years ago

Read 2 more answers

A. Telephone signals are often transmitted over long distances by microwaves. What is the frequency of microwave radiation with

zzz [600]

(a) 10 GHz is the frequency of microwave radiation.

(b) 0.167 ms is required by the microwave to travel between two mountains.

Answer:

Explanation:

(a). 1 MHz is the frequency of microwave radiation.

(b) 0.167 ms is required by the microwave to travel between two mountains.

Answer:

Explanation:

a. Frequency is the measure of number of times a same thing will be repeated in a given time interval for a given time. And wavelength is the measure of distance between two successive crests or troughs. So wavelength and frequency are inversely proportional to each other. And velocity of light is the proportionality constant.

So frequency of microwave radiation = Speed of light/Wavelength of radiation

Frequency = $\frac{3*10^{8} }{3*10^{-2} }$

Frequency = $10^{8+2} = 10^{10}=10 GHz$

So 10 GHz is the frequency of microwave radiation.

b). As microwave is a part of light waves, so it will be experiencing the speed of light.

As the speed is 3* $10^{8}$ m/s and the distance between the two mountains is given as 50 km, then time can be calculated as

Time = Distance/Velocity

Time = $\frac{50*10^{3} m}{3*10^{8} }=16.67*10^{3-8}=16.67*10^{-5}$

So time = 0.167 ms.

Thus, 0.167 ms is required by the microwave to travel between two mountains.

6 0

3 years ago

Why is the earth sphered but we cant fall off

anygoal [31]

Because of Gravity, Basically a force so strong it constantly pulls us to the earth with 1 G (Maybe 100 pounds of force constantly pulling us to the earth)

3 0

3 years ago

A girl attempts to drink a large glass of water without stopping. when she finishes, she gasps for air as she was unable to brea

katrin [286]

The behaviour that has just been displayed by the girl is an example of a learned behavior.

<h3>What is learned behaviour?</h3>

The term learned behaviour has to do with those behaviour that the individual acquires by practise and are not innate in the organism. The ability to drink a large amount of water without breathing is not inate in man.

Hence, the behaviour that has just been displayed by the girl is an example of a learned behavior.

Learn more about learned behavior:brainly.com/question/347230

#SPJ4

4 0

1 year ago

Nicole throws a ball at 25 m/s at an angle of 60 degrees abound the horizontal. What is the range of the ball?

just olya [345]

Answer:

the range or the ball is 48.81 m

Explanation:

given;

Nicole throws a ball at 25 m/s at an angle of 60 degrees abound the horizontal.

find:

What is the range of the ball?

solution:

let Ф = 25°

Vo = 25 m/s

<u>consider x-motion using time of fight: x = Vox * t</u>

where x = R = range

t =<u> 2 Voy </u>

R =<u> Vo² sin (2Ф)</u>

plugin values into the formula:

R = <u>(25)² sin (2*25) </u>

9.81

R = 48.81 m

therefore, the range or the ball is 48.81 m

4 0

3 years ago

Read 2 more answers