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3 years ago

Why does the background radiation in the universe have a temperature of 3ºC above absolute zero?

1 answer:

5 0

The background radiation is associated with a temperature of about 2.73 Kelvins (not Celsius). There is no particular reason for it to be at this specific value. This temperature is a snapshot of an ongoing process taken at our point in time. This temperature continues to change from where it used to be - many orders of magnitude higher in the early stages of our universe model - to today's measured value. The expanding universe view implies this temperature continues to decline as the universe expands, as you pointed out. It is just happening on an extremely slow time scale that we consider this value to be a constant.

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What do an earthquake wave and a light wave have in common?

rusak2 [61]

It’s c.) I think so at least

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Bill leaves his 60 W desk lamp on every day, including weekends, for eight hours. After one month (30 days), how much total ener

maxonik [38]

' W ' is the symbol for 'Watt' ... the unit of power equal to 1 joule/second.

That's all the physics we need to know to answer this question.
The rest is just arithmetic.

(60 joules/sec) · (30 days) · (8 hours/day) · (3600 sec/hour)

= (60 · 30 · 8 · 3600) (joule · day · hour · sec) / (sec · day · hour)

= 51,840,000 joules
__________________________________

Wait a minute ! Hold up ! Hee haw ! Whoa !
Excuse me. That will never do.
I see they want the answer in units of kilowatt-hours (kWh).
In that case, it's

(60 watts) · (30 days) · (8 hours/day) · (1 kW/1,000 watts)

= (60 · 30 · 8 · 1 / 1,000) (watt · day · hour · kW / day · watt)

= 14.4 kW·hour

Rounded to the nearest whole number:

14 kWh

7 0

3 years ago

What is the acceleration of the the object during the first 4 seconds?

AVprozaik [17]

Answer:

Velocity (m/s) over time (s) graph

We could write out our average acceleration as:

a = Δv/ Δta=Δv/Δta, equals, Δ, v, slash, Δ, t

a = (15 m/s - 0 m/s) / 0.2 seconds

a = 15 m/s / 0.2 seconds

a = 75 m/s / second

Explanation:

What this formula is telling us is that if we know the acceleration of an object, and the ... we can plug in our acceleration of 12.5 m/s2 for a, and 4 seconds for t.

Velocity (m/s) over time (s) graph

We could write out our average acceleration as:

a = Δv/ Δta=Δv/Δta, equals, Δ, v, slash, Δ, t

a = (15 m/s - 0 m/s) / 0.2 seconds

a = 15 m/s / 0.2 seconds

a = 75 m/s / second

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3 years ago

The form of energy given off by the vibrating strings of the violin is? A. Electrical Energy B. Potential Energy C. Radiant Ener

S_A_V [24]

Answer:

D . Sound energy

Explanation:

When the strings of a violin vibrate it produces sound which is sound energy. Due to the vibration of the strings the air present near the strings also vibrate in resonance with the strings. This compreesion and decompression's produced in the air is nothing but the sound. So the form of energy given off by the vibrating strings of the violin is Sound energy.

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3 years ago

Which term describes the reaction process in a fission reaction?

klasskru [66]

The correct answer is

A. Chain reaction

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1) Slow-moving neutrons reach heavy, unstable, radioactive nuclei (such as Uranium-235)

2) The neutrons interact with the nuclei of Uranium, which break apart producing smaller nuclei and additional neutrons

3) The neutrons produced in the reaction are slowed down by a moderator (e.g. water) and they interact with new nuclei of Uranium, causing new fission reactions)

4) The new neutrons interact with new nuclei of Uranium, and so on...

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