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liubo4ka [24]
2 years ago
15

Scientists often use models to study the movement of continents. Why might scientists use a model to show this movement? A. Extr

emely fast movement is not easily observed directly. B. Extremely slow movement is not easily observed directly. C. Extremely complex movement is not easily observed directly. D. Extremely dangerous movement is not easily observed directly.​
Physics
2 answers:
zloy xaker [14]2 years ago
5 0

Answer: the answer is B. Extremely slow movement is not easily observed directly.

egoroff_w [7]2 years ago
3 0

Answer:

Paleontologists have argued for a long time that the demise of the dinosaurs was caused by climatic alterations associated with slow changes in the positions of continents and seas resulting from plate tectonics. Off and on throughout the Cretaceous (the last period of the Mesozoic era, during which dinosaurs flourished), large shallow seas covered extensive areas of the continents. Data from diverse sources, including geochemical evidence preserved in seafloor sediments, indicate that the Late Cretaceous climate was milder than today's. The days were not too hot, nor the nights too cold. The summers were not too warm, nor the winters too frigid. The shallow seas on the continents probably buffered the temperature of the nearby air, keeping it relatively constant.

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Combine Newton's 2nd law and Hooke's law for a spring to find the acceleration of the block a(t) as a function of time. Express
Inga [223]

Answer:

a=-\dfrac{k}{m}x(t)

Explanation:

From Newton's second law,

F = ma

where F is the force, m is the mass and a is the acceleration.

From Hooke's law,

F = -kx(t)

where k is the spring constant and x(t) is the displacement function measured from the origin. The negative sign indicates the force acts in opposite direction to the displacement. In fact, it is a restoring force; it acts to return the spring to its original undisturbed position.

Since both forces are the same,

F = ma= - kx(t)

a=-\dfrac{k}{m}x(t)

The implication of this is that the acceleration is proportional to the displacement but opposite to it. That last statement is the definition of a simple harmonic motion which this is.

The ratio \dfrac{k}{m} is a constant except in situations where the mass is varying (say, the mass on the spring is a decaying material).

4 0
2 years ago
For metalloids on the periodic table, how do the group number and the period number relate?
lapo4ka [179]
Im guessing it's (a) since the numbers go in chronological order and you read the periodic table left to right
3 0
2 years ago
Read 2 more answers
Un tubo de acero de 40000 kilómetros forma un anillo que se ajusta bien a la circunferencia de la tierra. Imagine que las person
Darina [25.2K]

Answer:

82.76m

Explanation:

In order to find the distance of the steel ring to the ground, when its temperature has raised by 1°C, you first calculate the radius of the steel tube before its temperature increases.

You use the formula for the circumference of the steel ring:

C=2\pi r    (1)

C: circumference of the ring = 40000 km = 4*10^7m (you assume the circumference is the length of the steel tube)

you solve for r in the equation (1):

r=\frac{C}{2\pi}=\frac{4*10^7m}{2\pi}=6,366,197.724m

Next, you use the following formula to calculate the change in the length of the tube, when its temperature increases by 1°C:

L=Lo[1+\alpha \Delta T]         (2)

L: final length of the tube = ?

Lo: initial length of the tube = 4*10^7m

ΔT = change in the temperature of the steel tube = 1°C

α: thermal coefficient expansion of steel = 13*10^-6 /°C

You replace the values of the parameters in the equation (2):

L=(4*10^7m)(1+(13*10^{-6}/ \°C)(1\°C))=40,000,520m

With the new length of the tube, you can calculate the radius of a ring formed with the tube. You again solve the equation (1) for r:

r'=\frac{C}{2\pi}=\frac{40,000,520m}{2\pi}=6,366,280.484m

Finally, you compare both r and r' radius:

r' - r = 6,366,280.484m - 6,366,197.724m = 82.76m

Hence, the distance to the ring from the ground is 82.76m

4 0
2 years ago
Dentists' chairs are examples of hydraulic-lift systems. If a chair weighs 1400 N and rests on a piston with a cross-sectional a
NeX [460]

Answer:

Force applied to smaller cross section is

= 82.63 N

Explanation:

As we know

F_2 A_1 = F_1 A_2

where F1, F2 signifies the weight of the two chair in a hydraulic-lift system

And A_1, A_2 signifies the area of the two respective chairs in a hydraulic-lift system

Given -

F2=1400 N

A1 =1220 Square centimeter

A_2 = 72 Square centimeter

Substituting the given values in above equation, we get -

1400 * 72 = F1 * 1220\\F2 = 82.63

Force applied to smaller cross section is

= 82.63 N

8 0
2 years ago
Two resistors ( 3 ohms & 6 ohms) in a series circuit with a power supply = 12 volts. The current through resistor 6 ohms is
Scorpion4ik [409]

In a series circuit . . .

-- The total resistance is the sum of the individual resistors.

-- The current is the same at every point in the circuit.

The total resistance in this circuit is (3Ω + 6Ω )  =  9Ω

The current at every point is (V/R) = (12v / 9Ω ) = <em>1.33 A</em> .

Pick choice<em> (a)</em>.

6 0
1 year ago
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