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ella [17]
3 years ago
6

A stone dropped from the top of a 80m high building strikes the ground at 40 m/s after falling for 4 seconds. The stone's potent

ial energy with respect to the ground is equal to its kinetic energy … (use g = 10 m/s 2)
A) at the moment of impact.
B) 2 seconds after the stone is released.
C) after the stone has fallen 40 m.
D) when the stone is moving at 20 m/s.

At the moment of impact both Kinetic Energy and Potential Energy should be 0, right? So it can't be A), right? Or is this wrong? Is it indeed A)? Please show work and explain it well.
Physics
1 answer:
Sergeu [11.5K]3 years ago
3 0

Answer: c. 40m

Explanation:

See picture

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Answer: The correct answer is A). Animal burrow because burrow fossils represent the preserved byproducts of behavior rather than physical remains, they are considered a kind of trace fossil. One common kind of burrow fossil is known as Skolithos, and the similar Trypanites, Ophiomorpha and Diplocraterion.

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Identify and define the four major forms of matter, explain how melting, freezing, boiling,
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There are four forms of matter: Solid, Liquid, gas and Plasma and matter undergoes various state changes termed as melting, freezing, boiling, evaporation, condensation, sublimation and deposition.

<u>Explanation:</u>

Solids

A matter that have a definite shape because of its closely packed molecular structure; are known as Solids. It can be identified as they have a definite shape and cannot flow or float without external forces are applied.

Liquids

These have a an internal molecular structure with comparatively more spaces with one another. Liquids have a property to flow and change shape according to the container it is taken.

Gases

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Plasma

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<u>Phase transformation among the four forms of matter</u>

<u>Melting</u>

A matter changing from a solid phase to liquid phase is known as melting. Ex: Ice into water

<u>Freezing</u>

A matter changing from liquid to solid is known as freezing.

<u>Boiling</u>

When the liquid is heated to its boiling point, this gets transformed into the state of gas where liquid's pressure equals to the external pressure.

<u>Evaporation</u>

Once the liquid reached the temperature range above the boiling point ad starts converting into vapours or gaseous state.

<u>Condensation</u>

When the gases changes from the gaseous phase to liquid phase, this is called condensation.

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3 0
3 years ago
there is a fish called an archer fish that shoots drops of water at insects resting on branches above the water. If the Archer f
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Answer:

=3.5 m/s

Explanation:

y = x tanθ - 1/2 g x² / (u²cos²θ )

y = 0.25 , x = 0.5, θ = 40°

.25 = .50 tan40 - .5 x 9.8x x²/ u²cos²40

.25 = .42 - 2.0875/u²

u = 3.5 m / s.

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Explanation:

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Answer:

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