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3 years ago

A boy is pulling his two sisters on a sled.

Physics

1 answer:

OlgaM077 [116]3 years ago

4 0

Answer:

Explanation:

The oly way we can figure this out is if the boy is pulling the sled at a constant velocity. If not, we need a value for acceleration, and you don't have that here. If the boy is pulling the sled at a constant velocity, then the value for acceleration is 0, making this a really simple problem. I'm going with that, since there is no way to answer you otherwise. If velocity is not constant, please either repost the question or put it in the notes section under the question as it stands. If acceleration is 0, then

F - f = ma becomes

F - f = m(0) which is

F - f = 0 and

F = f which says that the applied force is the same as the frictional force. We need then to find the frictional force, which has an equation of

f = μ $F_n$ where normal force is the same as the weight of the 2 girls. We will find that, then:

Each girl's mass is different so the normal force/weight equation is

w = (30.0)(9.8) + (40.0)(9.8) to get

w = 290 + 390 and

w = 680. Plug that into the frictional force equation:

f = (.120)(680) so

f = 82N

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klemol [59]

Answer:

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Explanation:

When light is incident on a photoelectric material like metal, photoelectrons are emitted from the surface of the metal. This process is called photoelectric effect.

The relationship between the maximum kinetic energy ( $E_{k}$ ) of the photoelectrons to the frequency of the absorbed photons (f) and the threshold frequency (f₀) of the photoemissive metal surface is:

$E_{k}$ = h(f − f₀)

$E_{k}$ = hf - hf₀

E is the energy of the absorbed photons: E = hf

ϕ is the work function of the surface: ϕ = hf₀

$E_{k}$ = E - ϕ

Frequency f = 8.12×10¹⁸ Hz

Maximum kinetic energy $E_{k}$ = 4.16×10⁻¹⁷ J

Speed of light c = 3 x 10⁸ m/s

Planck's constant h = 6.63 × 10⁻³⁴ Js

E = hf = 6.63 × 10⁻³⁴ x 8.12×10¹⁸

E = 53.8356 x 10⁻¹⁶ J

from $E_{k}$ = E - ϕ ;

ϕ = E - $E_{k}$

ϕ = 53.8356 x 10⁻¹⁶ - 4.16×10⁻¹⁷

ϕ = 53.4196 x 10⁻¹⁶ J

The work function of the metal ϕ = 53.4196 x 10⁻¹⁶ J

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3 years ago

What is specific latent heat mean in simple word?

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Answer:

Amount of energy required to change the 1kg of a substance without changing its temperature.

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2 years ago

If the rotation of a planet of radius 5.32 × 106 m and free-fall acceleration 7.45 m/s 2 increased to the point that the centrip

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Answer:

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Explanation:

Given that,

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Also, the centripetal acceleration was equal to the gravitational acceleration at the equator.

We know that,

Centri[etal acceleration,

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3 years ago

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Answer:

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A virus.

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3 years ago

A uniform plank of length 6.1 m and mass 33 kg rests horizontally on a scaffold, with 1.6 m of the plank hanging over one end of

salantis [7]

Answer:

Explanation:

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3 years ago