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Nutka1998 [239]
2 years ago
11

A 20 watt lightbulb uses 20 Joules of energy every second.A person expends 50 watts of energy per stair when climbing up stairs.

How long could you light the lightbulb if the energy used to climb 20 stairs were converted to electricity?
Physics
1 answer:
Pachacha [2.7K]2 years ago
6 0
20W = 20 J/s

Energy expended during climbing stairs = 50 W of energy/stair = 50J/stair

For 20 stairs, Total energy = 50x20 = 1000 J

This can light bulbs for, T= 1000J/20 J/s =50 seconds
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A man climbs a ladder. Which two quantities can be used to calculate the energy stored of the man at the top of the ladder.
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Answer:The answer must be The weight of the man and the vertical distance moved.

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As a rough approximation, the human body may be considered to be a cylinder of length L=2.0m and circumference C=0.8m. (To simpl
Brilliant_brown [7]

Answer:

Thermal Power = 460W

Explanation:

From Stephan-Boltzmann Law Formula;

P = єσT⁴A

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P = Radiation energy

σ = Stefan-Boltzmann Constant

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є = Emissivity of the material.

A=Area of the emitting body

Now, σ = 5.67 x 10^(-8)

є = 0.6

Temperature = 30°C and coverting to kelvin = 30 + 273 = 303K

Area ; since we are to consider the sides of the human body as 2m and 0.8m,thus area = 2 x 0.8 = 1.6

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4 0
2 years ago
(HELP!!! 30 pts if answered right. )What formula gives the strength of an electric field, E, at a distance from a known source c
umka2103 [35]

Answer:

E=\frac{k\,Q}{d^2}

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Xelga [282]

Answer:

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