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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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A 75.5 kg diver drops from a diving board 10.0 m above the waters surface. Find the divers speed just before he strikes the wate
jenyasd209 [6]

Answer:

<em>v=14 m/s</em>

Explanation:

<u>Mechanical Energy </u>

The kinetic energy of a body (K) is the capacity of doing work due to its speed. It can be expressed as

\displaystyle K=\frac{mv^2}{2}

The potential energy (U) is the capacity of doing work due to its height respect to a certain reference level.

U=mgh

The  mechanical energy is the sum of both

\displaystyle E_m=\frac{mv^2}{2}+mgh

The principle of conservation of mechanical energy states it must remain the same if no external force is acting on it. The diver drops from the diving board, which means its initial speed is zero (and so its initial kinetic energy). Thus, the mechanical energy at the jumping time is

\displaystyle E_m=mgh=(75)(10)(9.8)=7350\ J

When the diver is about to get into the water, his height reaches zero and the speed is at maximum. All the potential energy became kinetic energy, so

\displaystyle \frac{mv^2}{2}=7350\ J

Rearranging

\displaystyle v^2=\frac{2(7350)}{75}=196

v=\sqrt{196}=14\ m/s

The final speed of the diver is

\boxed{v=14\ m/s}

8 0
3 years ago
How can you incorporate the information
il63 [147K]

Explanation:

There are many ways to achieve a healthier lifestyle and increase fitness. Healthy eating and constant exercise are essential for maintaining good physical and mental health. Through effective nutrition the human body is able to function better, there is an increase in disposition, improvement in immunity, improvement in blood rates, etc. Physical exercise, on the other hand, assists in strengthening muscles, controlling blood pressure, preventing cardiovascular disease, greater satisfaction, less stress, etc.

Some simple examples that can assist in improving health and fitness are:

  • Reduction of processed foods, sugars and soft drinks.
  • Increased fiber intake
  • Daily walks of at least 30 minutes
  • Increased water consumption
  • Increased consumption of fruits and vegetables
  • Incorporate meditation and yoga practices
6 0
3 years ago
Every football field has two 300kg field goal posts separated by 110m of football field (that includes the endzones). What is th
Mama L [17]

Answer:

4.96×10¯¹⁰ N

Explanation:

The following data were obtained from the question:

Mass 1 (M1) = 300 Kg

Mass 2 (M2) = 300 Kg

Separating distance (r) = 110 m

Gravitational constant (G) = 6.67×10¯¹¹ Nm²/Kg²

Gravitational force (F) =?

The gravitational force between the two goal posts can be obtained as follow:

F = GM1M2 / r²

F = 6.67×10¯¹¹ × 300 × 300 / 110²

F = 6.003×10¯⁶ / 12100

F = 4.96×10¯¹⁰ N

Therefore the gravitational force between the two goal posts is 4.96×10¯¹⁰ N

3 0
2 years ago
Describe a situation in your everyday life where you could use the scientific method. List all the steps of the scientific metho
emmainna [20.7K]

Yes, scientific method can be applied on many everyday activities to get a reasonable solution. Infact normally we are applying this method without having it in our knowledge that we are applying it.

For example: In morning we are going to office and we start the car, but it is not started.You turn the engine again and again but it simply donot works.

Observation (the state of defining a problem):

The car is not started

Hypothesis (A possible solution based on the information we already know):

The car is not started because it might be out of gas or there can be some other technical fault.  

Experiment (testing of hypothesis by applying different methods of solving problem):

You get the fuel and put it inside the car but it still donot works and car didnot start. Experiment didnot get solution.

Analyze the results of data and test another hypothesis

You call a technician and he check with the car engine tries and finds out that the engine was out of order and needs repairing.

Draw conclusion:

The engine do not works when it is out of order and it is a cause of a car not being started.

<em>Now the theory and law making part can not be applied on this case but it is a part of scientific method.</em>

Hope it helps!

8 0
3 years ago
a car is moving with a constant speed of 20 meters per second.What total distance does the car travel in 2 minutes
N76 [4]
There are 120 seconds in two minutes, so to find the answer, you multiply 20 x 120 to get 2400 meters.
8 0
3 years ago
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