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PSYCHO15rus [73]
3 years ago
7

A sound system is designed to produce a 1.0W/m2 sound intensity over the surface of a hemisphere 20 m in radius. What acoustic p

ower is needed from an array of speakers at the center of the sphere?
Physics
1 answer:
Marina CMI [18]3 years ago
3 0

Answer:

2513.6 W

Explanation:

Acoustic power = sound intensity × area of hemisphere

Sound intensity = 1 W/m^2

Area of hemisphere = 2πr^2 = 2×3.142×20^2 = 2513.6 m^2

Acoustic power = 1 W/m^2 × 2513.6 m^2 = 2513.6 W

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Explanation:

What is density?

Density is the amount of substance per unit volume. It is simply mass divided by volume.

Density is greatly influenced by the way substances are packed.

Substances that are well packed will have lower volume for the same amount of matter than another that is poorly packed.

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Since:

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Answer: The force of kinetic friction is smaller than that of static friction, but F_g  remains the same.

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The physical explanation for this, that friction force adopts any value needed to avoid to move the object, till a limit value is achieved, called static friction force, equal to the normal force times the static friction coefficient.

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In the case of the box sliding down the board, the force that tries to move the object down the board, is the component of the weight parallel to the board, that can be showed that being equal to the weight times the sinus of the angle of the board with the horizontal, as follows:

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In the limit, when θ=90º, sin θ =1⇒ F_g = mg, so the object is in free fall.

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