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2 years ago

Why should people pay attention to scientists when making decisions?

Physics

1 answer:

olga nikolaevna [1]2 years ago

6 0

Answer:

D. Scientist back up their statements with facts.

Explanation:

The majority of the laws, theorems and thesis are base on with experiments. The follow different strategies for confirm the hypothesis with facts, one of the most famous models is the scientific method. That is a way of proof something in a trustworthy.

In the image is the resume about this method (graphical organizer).

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One gallon of paint covers an area of 25 m2. What is the thickness of the paint on the wall?

Flura [38]

Answer:

Explanation:

1 gal = 231 in³

231 in³ (2.54³ cm³/in³) = 3,785.411784 cm³

3,785.411784 cm³ (0.01³ m³/cm³) = 0.003785411784 m³

0.003785411784 m³ / 25 m² = 0.00015141647136 m

or approximately 0.15 mm

6 0

2 years ago

While the negatively charged rod is near the disk without touching it, a hand briefly touches the end of the post. Then the nega

Paraphin [41]

Answer:

that initially the weather vane was at rest, by this load that remained on the pole it would begin to move.

Explanation:

Let us carefully analyze the situation, when the bar is facing the index post a load of equal magnitude, but opposite sign on its surface, these two charges are in balance; When the hand touches the pole, it creates a path to the ground where the charges that were induced on the pole can be balanced with the charge coming from the ground, leaving a zero charge on the pole.

Now if the hand is removed, there can be no exchange of charges with the earth. When the bar is removed, the induced loads are redistributed in the post, but the excess loads that came from the earth that have the same value and are of a sign opposite to the induced ones remain, you want to sign that they are of the same sign as the charges of the bar.

In summary, after the process, the post has a load of equal magnitude and sign (negative) that of the bar.

If we assume that initially the weather vane was at rest, by this load that remained on the pole it would begin to move.

4 0

3 years ago

"When Baby Ian is held horizontally on his back, he sometimes makes an embracing motion by arching his back, extending his legs,

Burka [1]

Answer:

Moro reflex

Explanation:

The baby has a series of reflexes in its first months of life and they are very important for the good development of the little ones. One of them is the Moro Reflex. In this reflection, the baby spreads his arms wide, stretches his legs and extends his neck. Moro's reflex begins from birth and continues until about four months of the baby. It occurs when the baby abruptly shifts position or falls backwards or feels in an insecure position, at which time the baby makes a hug movement by arching his back, extending his legs, throwing his arms out and then bringing his arms. towards the body.

4 0

3 years ago

A rocket engine has a chamber pressure 4 MPa and a chamber temperature of 2000 K. Assuming isentropic expansion through the nozz

gladu [14]

This question is incomplete, the complete question is;

A rocket engine has a chamber pressure 4 MPa and a chamber temperature of 2000 K. Assuming isentropic expansion through the nozzle, and an exit Mach number of 3.2, what are the stagnation pressure and temperature in the exit plane of the nozzle? Assume the specific heat ratio is 1.2.

Answer:

- stagnation pressure is 274.993 Mpa

- the stagnation temperature Tt is 4048 K

Explanation:

Given the data in the question;

To determine the stagnation pressure and temperature in the exit plane of the nozzle;

we us the expression;

Pt/P = (1 + (γ-1 / 2) M²)^(γ/γ -1) = ( Tt/T )^(γ/γ -1)

where Pt is stagnant pressure = ?

P is static pressure = 4 MPa = 4 × 10⁶ Pa

Tt is stagnation temperature = ?

T is the static temperature = 2000 K

γ is ratio of specific heats = 1.2

M is Mach number M = 3.2

we substitute

Pt/P = (1 + (γ-1 / 2) M²)^(γ/γ -1)

Pt = P(1 + (γ-1 / 2) M²)^(γ/γ -1)

Pt = 4 × 10⁶(1 + (1.2-1 / 2) 3.2²)^(1.2/1.2 -1)

Pt = 4 × 10⁶ × 68.7484

Pt = 274.993 × 10⁶ Pa

Pt = 274.993 Mpa

Therefore stagnation pressure is 274.993 Mpa

Now, to get our stagnation Temperature

Pt/P = ( Tt/T )^(γ/γ -1)

we substitute

274.993 × 10⁶ Pa / 4 × 10⁶ Pa = ( Tt / 2000 )^(1.2/1.2 -1)

68.7484 = Tt⁶ / 6.4 × 10¹⁹

Tt⁶ = 68.7484 × 6.4 × 10¹⁹

Tt⁶ = 4.3998976 × 10²¹

Tt = ⁶√(4.3998976 × 10²¹)

Tt = 4047.999 ≈ 4048 K

Therefore, the stagnation temperature Tt is 4048 K

6 0

3 years ago

What is your acceleration while sitting in your chair. the latitude of corvallis is 44.4˚.?

marta [7]

<span>You can start with the equations you know

a=v^2/r = (2pi*r/T)^2/r = 4pi^2r/T^2

Radius of earth (R) = 6378.1 km
Time in one day (T) = 86400 seconds
Latitude = 44.4 degrees

If you draw a circle and have the radius going out at a 44.4 degree angle above the center you can then find the r.

r=Rcos(44.4)
r=6378.1cos(44.4)
r= 4556.978198 km or 4556978 m

Now you can plug this value into the acceleration equation from above...

a= 1.8*10^8/7.47*10^9
a= .0241 m/s^2 </span>

8 0

3 years ago