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Marat540 [252]
3 years ago
15

Where conventional relays, contactors and switches, which have arcing contacts, are installed in Class I, Division 1 and 2 locat

ions, they must be enclosed in ? .
Physics
1 answer:
solmaris [256]3 years ago
7 0

Answer:

They must be enclosed in explosion proof housing or general-purpose housing (as per NEC Regulations)

Explanation:

It is important to know what are Class I, Division 1 and 2 locations.

Class I: includes those industries or places where flammable gases exists and there are chances of explosions.

Division 1: Those places where hazard can happen under normal operating conditions

Division 2: Those places where hazard can happen under abnormal conditions.

The conventional relays, contactors and switches cause arcing when they operate and this is a completely normal phenomenon but with respect to these categories, it is very dangerous to operate such electrical devices without any precaution.

Therefore industries are required by the regulatory authorities to install  explosion proof housing to enclose conventional relays, contactors and switches to avoid any explosion or hazard. General-purpose housing can also be used given that it follows the regulations provided by the NEC or any other regulatory authority.

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What is the motional kinetic energy of a 25 kg object moving at a speed of 10 m/s?
Soloha48 [4]

1250kgm²/s is the motional kinetic energy of a 25kg object moving at a speed of 10m/s

Kinetic energy of an object is defined as the energy which is possessed when that is  in motion. It is the energy of the kinetic mass of an object. Kinetic energy is never negative and is a scalar quantity. That is, it shows only size, not orientation.

Given to us

Mass of the object, m=25kg

Velocity of the object, v=10m/s  

K.E=1/2x25x10²

 =1250

Kinetic energy is directly proportional to the mass and velocity squared (K.E.) of an object. =1/2xMxV². If the mass is in kilograms and the velocity is in meters/second, then the kinetic energy is in kilograms - meters squared/second.

Learn ore about Kinetic energy here brainly.com/question/25959744

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5 0
8 months ago
The speed of sound in aluminum is 5200 m/s. Can you hear a sound with a
romanna [79]

Answer:

v = wavelength * frequency

frequency = 5200 m/s / .2 m = 26000 / sec

20,000 / sec is optimistic for the upper frequency of human hearing

So 26,000 is above the hearing range for human ears

5 0
2 years ago
A 1000-kg car is moving at 30 m/s around a horizontal unbanked curve whose diameter is 0.20 km. What is the magnitude of the fri
omeli [17]

Answer:

4500 N

Explanation:

When a body is moving in a circular motion it will feel an acceleration directed towards the center of the circle, this acceleration is:

a = v^2/r

where v is the velocity of the body and r is the radius of the circumference:

Therefore, a body with mass m, will feel a force f:

f = m v^2/r

Therefore we need another force to keep the body(car) from sliding, this will be given by friction, remember that friction force is given a the normal times a constant of friction mu, that is:

fs = μN = μmg

The car will not slide if     f = fs,   i.e.

fs = μmg =  m v^2/r

That is, the magnitude of the friction force must be (at least) equal to the force due to the centripetal acceleration

fs = (1000 kg)  * (30m/s)^2 / (200 m) = 4500 N

7 0
3 years ago
Read 2 more answers
in a lever, a load of 600N is lifted by using 400 effort. If the load is at the distance of 20cm and the effort at the distance
koban [17]

Explanation:

Load (l) = 680N

Effort (E) = 500N

Length slope (l) = 12m

Height slope (h) = 8 m

Output = load * height

680 *8 = 5.44 *103 J

The Input = effort * length = 500 *12 = 6000J

the Mechanical advantage (M.A) = load effort= 600500=1.36

the Velocity ratio (V.R) =lh=128 = 1.5

the Efficiency =M.A100%V.R= 90.6%

8 0
2 years ago
Gases are more prone to expansion and contraction than liquid . The biggest change in the volume in your thermometer was probabl
KiRa [710]

Answer:

In the air

Explanation:

There are three states of matter:

- Solids: in solids, the particles are tightly bond together by strong intermolecular forces, so they cannot move freely - they can only vibrate around their fixed position

- Liquids: in liquids, particles are more free to move, however there are still some intermolecular forces keeping them close to each other

- Gases: in gases, particles are completely free to move, as the intermolecular forces between them are negligible

For this reason, it is generally easier to compress/expand the volume of a gas with respect to the volume of a liquid.

In this problem, we are comparing water (which is a liquid) with air (which is a gas). From what we said above, this means that the change in volume is larger in the air rather than in the water.

8 0
2 years ago
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