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xenn [34]
3 years ago
8

What is dark energy?

Physics
1 answer:
olga2289 [7]3 years ago
6 0

Explanation:

Dark Energy. Dark Energy is a hypothetical form of energy that exerts a negative, repulsive pressure, behaving like the opposite of gravity. It has been hypothesised to account for the observational properties of distant type Ia supernovae, which show the universe going through an accelerated period of expansion

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Why can't we say a measurement tool is accurate?
sashaice [31]

There are various reasons why a measurement tool cannot be accurate. One of them is thermal contraction and expansion varies according to seasons.

<h3>What are Accuracy and Precision?</h3>

There are two ways to assess observational error: accuracy and precision. Precision measures how closely two measurements are to one another, whereas accuracy measures how close a group of measurements is to its actual value. In other words, precision is a measure of statistical variability and a description of random errors.

We can say that a tool can be precise, but it cannot be accurate. There are various reasons behind that, some of them are :

  • It may not be calibrated properly. If there are no reliable standards to use for calibration, this may occur.
  • Perhaps it strayed. This is why electronic scales include a tare function—they are terrible in this area.
  • Perhaps the measurements are not linear. Our calipers might have been quite precise at the 2-inch standard, where they were calibrated, but inaccurate at other dimensions.
  • Temperature is one environmental component that the instrument might be sensitive to. These effects might be compensated for, but the compensation might not be ideal. This issue affects both dissolved solids meters and picometers.

These are some of the reasons due to which measurement tool cannot be accurate.

To get more information about Accuracy and Precision :

brainly.com/question/15276983

#SPJ1

7 0
2 years ago
Desceibe how the ringing sound of a telephone
luda_lava [24]
<span>buzzed, droned, jangled, reverberated.</span>
5 0
3 years ago
What is an example of frequency
emmasim [6.3K]

'Frequency' is a word that often confuses some people ... for no good reason.
It just means "frequent-ness" or "often-ness" ... how often something happens.

The SI unit of frequency is the Hertz (Hz).  Hz means 'per second'.
So  " 13 Hz "  means  13 per second.

Here are examples of frequency:

-- 780 kilohertz (on your AM radio dial)
-- 98.7 Megahertz (on your FM dial)
-- 5.8 Gigahertz
-- twice a day
-- three per week
-- every 6 months

6 0
4 years ago
Read 2 more answers
What is the most effective way to clean the science desks? <br><br> Hypothesis:
lukranit [14]
The most effective way to clean a science desks is to use a soapy water solution to clean tables using a clean disposable paper towel. Second, after cleaning the table surface with soap or detergent and rinsing with water, disinfect tables by using a diluted bleach water solution
6 0
3 years ago
A hot air balloon traveled 3 hours at a speed of of 450 km/hr. What distance did it travel?
erastova [34]

Answer:

it traveled 1350 kilometers or 839 miles

Explanation:

You just have to do 450 times three because its 3 HOURS and 450 kilometers per HOUR.

3 0
3 years ago
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