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lisov135 [29]
4 years ago
15

A room that has an average ambient sound pressure level of 62 dBA and a maximum sound pressure level lasting more than a minute

at 68 dBA must have a public mode signal that is at least ? .
Physics
1 answer:
cupoosta [38]4 years ago
6 0

Answer:

Explanation:

A fire alarm notification appliance is an active fire protection component of a fire alarm system. The primary function of the notification appliance is to alert persons at risk.

If want the audible public mode signal to be hear clearly then, we need to have a sound level that is at least 15dB above the average ambient sound level or 5dB above the maximum sound level of at least 1minute

In this case the,

The average ambient sound level is 62dB,

And the maximum sound level is 68dB

Then, the public mode signal should be at least

1. 62dB+ 15dB=77dB

Or

2. 68dB +5dB =73dB.

Then the public mode signal hearing must be at least 77dB.

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Two positive point charges, each of which has a charge of 2.5 × 10−9 C, are located at y = + 0.50m and y = − 0.50m. Find the mag
Salsk061 [2.6K]

Answer:

The resultant electric force is 14.8N to the right.

Explanation:

Since the three charges aren't in the same line, we have to break down the force in components. First, we need to know the distance from the third charge to the other ones. That is made using the Pythagorean Theorem. As the figure is symmetric with respect to the x-axis, the two distances are the same:

r=\sqrt{(0.50m)^{2}+(0.70m)^{2}}=0.86m

Now, we use the Coulomb's Law to obtain the magnitude of the individual forces caused by each charge on the third charge:

|F_{13}|=k\frac{q_1q_3}{r^{2}} \\\\|F_{13}|=(9*10^{9}Nm^{2}/C^{2})\frac{(2.5*10^{-9}C)(3.0*10^{-9}C)}{(0.86m)^{2}}\\\\|F_{13}|=9.1N

For the same reason the distances are the same, the magnitude of the forces are the same:

|F_{23}|=|F_{13}|=9.1N

So, to get the resultant force, we have to break down this forces in components. To do this, we need their angles with respect to the x-axis. Let θ₁ and θ₂ be these angles, respectively. Then, we calculate them using trigonometry:

\theta_1=\arctan(\frac{-0.50m}{0.70m})=-35.5\°\\\\\theta_2=\arctan(\frac{0.50m}{0.70m})=35.5\°

Now, we calculate the components of the forces:

F_{13}_x=F_{13}\cos\theta_1=9.1N\cos(-35.5\°)=7.4N\\\\F_{13}_y=F_{13}\sin\theta_1=9.1N\sin(-35.5\°)=-5.3N\\\\F_{23}_x=F_{23}\cos\theta_2=9.1N\cos(35.5\°)=7.4N\\\\F_{23}_y=F_{23}\sin\theta_2=9.1N\sin(35.5\°)=5.3N

Evidently, the y-components cancel out, and the resultant electric force on the third charge is 7.4N+7.4N=14.8N along the x-axis (to the right, because it's positive).

8 0
3 years ago
Rahul kept two plane mirrors at a certain angle in front of a burning candle. He could see 5 images of the candle in the mirrors
Goshia [24]

Answer:

The angle between the mirrors is 90°.

Explanation:

Given that,

Number of image = 5

Rahul kept two plane mirrors at a certain angle in front of a burning candle.

We need to find the angle between the mirrors

Using given data

When Rahul kept two plane mirrors at a certain angle in front of a burning candle then see the 5 image of candle in the mirrors.

If rahul kept two plane mirrors at a 90° then we get the 5 image of candle.

Firstly we see the two images in both mirror and now first image of first mirror is see in second mirror and second image of second mirror is see in first mirror.

So, we can say that we see the 5 image of candle in the mirrors.

Hence, The angle between the mirrors is 90°.

7 0
3 years ago
What happens to gravitational potential energy as a rollercoaster moves down a hill? Question 4 options: It is converted to elas
inysia [295]

The gravitational potential energy as a rollercoaster converts to kinetic energy when it moves downhill.

<h3>What is kinetic energy?</h3>

The kinetic energy of an object or body is due to its motion. When the roller coaster moves downhill it accelerates, thus the gravitational potential energy as a rollercoaster converts to kinetic energy.

The gravitational potential energy of an object or body is due to its position above the ground.


Therefore, the gravitational potential energy as a rollercoaster converts to kinetic energy when it moves downhill.

Learn more about kinetic energy:

brainly.com/question/1250558

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3 years ago
The ____ is a line drawn at a right angle to a barrier. a. normal c. node b. ray d. wave front
Natalija [7]

Answer:

a. normal

Explanation:

In the field of physics the normal is a line drawn at a right angle to a barrier. In other words the normal line is the line that is drawn perpendicular (right angle, 90 degrees) to the reflective surface of a mirror, or the particular boundary in which refraction occurs at the point of incidence of a light ray. This can be seen in the picture attached below.

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3 years ago
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The water formed on the surface of the water evaporation loss (evaporation), consisting of plant transpiration water loss (transpiration) is called. Soil near the plant and the resulting water loss is called by evapotranspiration.
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4 years ago
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