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charle [14.2K]
3 years ago
6

Calculate the change in potential energy of a 91.2 kg man when he takes an elevator from the first floor to 37th floor, if the d

istance between floors is 3.99 m.
Physics
1 answer:
MAXImum [283]3 years ago
3 0

Answer:

128379.69 J

Explanation:

Potential energy: This can be defined as the energy of a body to to position in the gravitational field. The S.I unit of potential energy is Joules (J).

The expression for potential energy is given as,

ΔEp  = mgΔH

ΔEp = mg(H₂-H₁)..................... Equation 1

Where ΔEp =change in  Potential Energy, m = mass of the man, g = acceleration due to gravity, H₂ = Height of the 37th floor, H₁ = height of the first floor

Given:m = 91.2 kg, g = 9.8 m/s², H₁ = 3.99 m, H₂ = 3.99×37 = 147.63 m.

Substitute into equation 1

ΔEp = 91.2(9.8)(147.63-3.99)

ΔEp = 893.76(143.64)

ΔEp = 128379.69 J.

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A bird sits on top of a 639 m tall tower. If it's gravitational potential energy up there is 2033 J, what is its mass?
iris [78.8K]

The mass of the bird is 0.32 kg.

<u>Explanation:</u>

Gravitational potential energy, the energy exhibited by an object at rest due to the influence of gravitational force. So the increase in distance of object from the surface of earth leads to increase in the gravitational potential energy. Thus,

       \text {Gravitational potential energy}=m \times \text { Acceleration } \times \text { Distance of bird from bottom }

So, as the gravitational potential energy is given as 2033 J and the position of bird placed on the tall tower is 639 m away from the bottom, then the mass (m) of the bird can be found as below.

       m o f \text { bird }=\frac{\text {Gravitational potential energy}}{a \times \text {Distance}}=\frac{2033}{9.8 \times 639}=\frac{2033}{6262.2}

So, finally we get the bird's mass as,

            m of bird = 0.32 kg

7 0
3 years ago
Tres litros de oxigeno gaseoso a 15 grados centígrados y a presión atmosférica (1atm), se lleva a una presión de 10mm de Hg. ¿ c
lana [24]

Answer:

Three liters of gaseous oxygen at 15 degrees Celsius and at atmospheric pressure (1atm), is brought to a pressure of 10mm Hg. What will be the volume of the gas now if the temperature has not changed?

Explanation:

Given that, the temperature is constant

Then, using gay Lussac law

P1•V1 / T1 = P2•V2 / T2

Since temperature is constant

Then, T1 = T2 = T and they cancels out

So, we are left with

P1•V1 = P2•V2

Given that, .

Initial volume

V1 = 3 litres.

Initial pressure

P1 = 1atm = 101325 Pa

Final pressure

P2 = 10mmHg = 1333.22 Pa

Then, we want to find the final volume V2

Make V2 subject of formula.

V2 = V1•P1 / P2

V2 = 3 × 101325 / 1333.22

V2 = 288 litres

So, the final volume is 288 litres.

In Spanish

Dado que la temperatura es constante

Luego, usando la ley gay de Lussac

P1 • V1 / T1 = P2 • V2 / T2

Como la temperatura es constante

Entonces, T1 = T2 = T y se cancelan

Entonces, nos quedamos con

P1 • V1 = P2 • V2

Dado que, .

Volumen inicial

V1 = 3 litros.

Presión inicial

P1 = 1atm = 101325 Pa

Presión final

P2 = 10 mmHg = 1333.22 Pa

Entonces, queremos encontrar el volumen final V2

Hacer V2 sujeto de fórmula.

V2 = V1 • P1 / P2

V2 = 3 × 101325 / 1333.22

V2 = 288 litros

Entonces, el volumen final es de 288 litros

8 0
3 years ago
An object is dropped from rest from the top of a 400 m cliff on Earth. If air resistance is negligible, what is the distance the
IrinaVladis [17]

Answer:

176.58 m

Explanation:

t = Time taken = 6 seconds

u = Initial velocity = 0

v = Final velocity

s = Displacement

g = Acceleration due to gravity = 9.81 m/s² = a

Equation of motion

s=ut+\dfrac{1}{2}at^2\\\Rightarrow s=0\times t+\dfrac{1}{2}\times 9.81\times 6^2\\\Rightarrow s=176.58\ m

The object travels 176.58 m from the cliff in 6 seconds.

8 0
3 years ago
What are two ways in which the suns energy can be captured and used?
My name is Ann [436]

The oldest way ... the way we've been using as long as we've been
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sun all day, capturing its energy and using it to make chemical compounds. 
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rip the chemical compounds apart and suck the solar energy out of them,
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Another way to capture the sun's energy is to build a dam across a creek
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up in the mountains, so the water still has most of that potential energy
as it drizzles down the river to the ocean.  If we catch it on its way, we
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photovoltaic cells.  Those are the flat blue things that you see on roofs
everywhere.  When the sun shines on them, they convert some of its
energy into electrical energy.  We use some of what they produce, and
we store the rest in giant batteries, to use when the sun is not there.
 
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3 years ago
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mario62 [17]
Temperature stays the same
4 0
3 years ago
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