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Andrews [41]
3 years ago
12

Scientific knowledge is both long lasting and open to change. In your own words, explain why scientific knowledge should be re-e

xamined and re-tested from time to time. Include two examples that will support your response.
Physics
2 answers:
Nostrana [21]3 years ago
7 0
Science is open to change because scientists agree that there are no absolute truths, only the best explanations for the data
there are specifically two cases when science can change: -new data is discovered (for example new skeleton makes us revise the known history of homo species)
-a new model is proposed that fits the data better (such as the heliocentric model of Copernicus)
Leviafan [203]3 years ago
3 0

Answer:

Open to change

Explanation:

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Olin [163]
To get this we need to know how long he was traveling. To know that we need to solve for the time it took for him to hit the ground. This is given by the vertical height he started at and the equation of motion for falling objects. The position function is
Y= -(9.8/2)t^2 + 50 = 0
t=3.19s
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And solve for v
100m/3.19s = 31.35m/s
3 0
4 years ago
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An ideal gas is compressed at constant pressure p=1500 Pa from a volume Vi=0.4 m3 to Vf=0.25 m3. At the same time, heat is trans
Anon25 [30]

To solve this problem we will apply the first law of thermodynamics and we will make a balance between the heat transferred, its internal energy and the total work. Recall that for gases the definition of work can be expressed in terms of its pressure and volume. Let's start

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dW = Work

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dQ = dW

dQ = PdV

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Finally, the expression of the heat transferred can be expressed in terms of pressure and volume, so it would end up becoming

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Replacing,

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3 0
4 years ago
How long does a 50 kW pump motor have to run to pump 500 cubic meters of water from a 180m deep mine
Ghella [55]

Answer:

t = 17658 s = 294.3 min = 4.9 h

Explanation:

The general formula for power is:

P = \frac{W}{t}

where,

P = Power of the Motor = 50 KW = 50000 W

W = Work Done by Motor = Change in P.E of Water = mgh

g = acceleration due to gravity = 9.81 m/s²

m = mass of  water = ρV

h = depth of water = 180 m

ρ = density of water = 1000 kg/m³

V = Volume of Water = 500 m³

t = time taken = ?

Therefore,

P = \frac{mgh}{t}=\frac{\rho Vgh}{t}\\\\t = \frac{\rho Vgh}{P}\\\\t = \frac{(1000\ kg/m^3)(500\ m^3)(9.81\ m/s^2)(180\ m)}{50000\ W}\\\\

<u>t = 17658 s = 294.3 min = 4.9 h</u>

6 0
3 years ago
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ohaa [14]

Answer:

the element that takes part in a chemical reactions

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except decomposition reactions

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I think the answer would be A.
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