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3 years ago

The Mesozoic Era is a time in Earth history when ________.

Physics

1 answer:

algol [13]3 years ago

6 0

Answer:

D. the dinosaurs appeared and came to dominate large-scale terrestrial life

Explanation:

The Mesozoic Era is a time in Earth history when

D. the dinosaurs appeared and came to dominate large-scale terrestrial life

The Mesozoic Era is the dinosaur age and lasted from approximately 250 to 65 million years ago for nearly 180 million years. This era includes three well-known periods called the periods of Triassic, Jurassic, and Cretaceous. A mass extinction marked the Mesozoic Era's beginning and end.

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La temperatura de cambio de estado, ¿Puede ser igual para todos los materiales? Justifica comparando dos materiales

Soloha48 [4]

Answer:

No.

Explanation:

Para darnos cuenta de esto tenemos que pensar en lo siguiente:

Pensemos en un vaso de vidrio, lleno de agua hasta la mitad, la otra mitad puede ser manteca derretida

Si metemos el vaso en la heladera durante un par de horas, (sabemos que la manteca en la heladera se mantiene sólida) veremos que la manteca se solidificó en la parte de arriba, mientras que el agua sigue líquida.

Entonces encontramos dos compuestos con distintas temperaturas para cambio de fase, pero materiales es más específico, y puede referirse a materiales puros.

Entonces vamos a dos metales:

Primero tenemos una pieza de hierro y una de mercurio en el congelador (supongamos que ambas están a 0°C).

Ahora los sacamos del congelador y los dejamos llegar a temperatura ambiente.

Como bien sabemos, el mercurio es líquido a temperatura ambiente, entonces el mercurio va a sufrir un cambio de fase

Ahora pensemos en el hierro; claramente va a seguir siendo sólido a temperatura ambiente, entonces podemos ver dos materiales cuyo cambio de fase de sólido a líquido ocurre en distintas temperaturas, por lo que podemos concluir que no, la temperatura de cambio de estado no puede ser igual para todos los materiales, y esto se debe a que la estructura atómica de todos los materiales es diferente.

8 0

3 years ago

A plane leaves the airport in Galisteo and flies 160 km at 66.0 ∘ east of north; then it changes direction to fly 260 km at 49.0

user100 [1]

The question doesn't have any particular requirement, but we'll compute the displacement of the plane from its initial and final landing point in the pasture

Answer:

$\displaystyle |\vec{r}|=321.464\ km$

$\displaystyle \theta =-19.395^o$

Explanation:

Displacement

The vector displacement $\vec r$ is a measure of the change of position of a moving object. The displacement doesn't depend on the path followed, only on the final and initial positions. Its scalar counterpart, the distance, does measure the total space traveled and considers all the changes in the direction taken by the object. To find the displacement, we must add all the particular displacements by using vectors.

The plane first flies 160 km at 66° east of north. To find the vector expression of this displacement, we must know the angle with respect to the East direction or North of East. Knowing the angle East of North is 66°, the required angle is 90°-66°=34°

The first vector is expressed as

$\displaystyle \vec{r_1}=\left \langle 160^o\ cos34^o, 160\ sin34^o \right \rangle$

$\displaystyle \vec{r_1}=\left \langle 132.646, 89.471 \right \rangle$

The second displacement is 260 km at 49° South of East. This angle is below the horizontal respect to the reference, thus we use -49°.

The second vector is expressed as:

$\displaystyle \vec{r_2}=\left \langle 260\ cos(-49^o), 260\ sin(-49^o)\right \rangle$

$\displaystyle \vec{r_2}=\left \langle 170.575,-196.224\right \rangle$

The total displacement is computed as the vectorial sum of both vectors

$\displaystyle \vec{r}=\vec{r_1}+\vec{r_2}=\left \langle 132.646+170.575\right \rangle+ \left \langle89.471-196.224\right \rangle$

$\displaystyle \vec{r}=\left \langle 303.221,-106.753\right \rangle\ km$

The magnitude of the total displacement is

$\displaystyle |\vec{r}|=\sqrt{303.221^2+(-106,753)^2}$

$\displaystyle |\vec{r}|=321.464\ km$

And the direction is

$\displaystyle tan\ \theta =\frac{-106.753}{303.221}=-0.352$

$\displaystyle \theta =-19.395^o$

6 0

3 years ago

Explain Resistor in parallel and series.

patriot [66]

$\sf\huge\underline\blue{Resistor:-}$

$\rightarrow$ A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element.

$\rightarrow$ Resistors reduce the current flow and lower voltage levels within circuits.

$\sf\large\underline\purple{Resistors \:in\: Series:-}$

$\rightarrow$ A circuit is said to be connected in series when the same amount of current flows through the resistors. In such circuits, the voltage across each resistor is different.

$\rightarrow$ In a series connection, if any resistor is broken or a fault occurs, then the entire circuit is turned off. The construction of a series circuit is simpler compared to a parallel circuit.

$\rightarrow$ For the above circuit(attached image-1), the total resistance is given as:

$\sf{R_{total}\: = \:R1 + R2 + ….. + Rn}$

The total resistance of the system is just the total of individual resistances.

$\sf\large\underline\purple{Resistors \:in\: Parallel:-}$

$\rightarrow$ A circuit is said to be connected in parallel when the voltage is the same across the resistors. In such circuits, the current is branched out and recombines when branches meet at a common point.

$\rightarrow$ A resistor or any other component can be connected or disconnected easily without affecting other elements in a parallel circuit.

$\rightarrow$ The figure(attached image -2) above shows ‘n’ number of resistors connected in parallel. The following relation gives the total resistance here

$\sf{\frac{1}{R_{total}}\: = \:\frac{1}{R1} + \frac{1}{R2} + ….. + \frac{1}{Rn}}$

$\rightarrow$ The sum of reciprocals of resistance of an individual resistor is the total reciprocal resistance of the system.

_______________________________

Hope it helps you:)

6 0

2 years ago

Read 2 more answers

A 91.5 kg football player running east at 2.73 m/s tackles a 63.5 kg player running east at 3.09 m/s. what is their velocity aft

pentagon [3]

Answer:

2.877 m/s

Explanation:

According to the laws of conservation of linear momentum,

the momentum of the moving objects before impact is equal to the momentum of the objects after impact (Assuming no external forces were applied)

Let both players are tackled and moving in V velocity

M and m - masses of the players
U and u - velocities of them respectively (both velocities are towards east direction )

momentum before impact = momentum after impact

→MU + →mu = →(M+ m )v

91.5 * 2.73 + 63.5 * 3.09 = (91.5 + 63.5) * V

→V = 2.877 m/s (To East)

3 0

3 years ago

Read 2 more answers

Resistor A has twice the resistance of resistor B. The two are connected in series and a potential difference is maintained acro

Ainat [17]

Answer:

The thermal energy dissipated in A would be twice that in B

Explanation:

Resistor B (RB)= R

Resistor A (RA)= 2 R

When they are connected in series the equivalent Resistance in the circuit would be;

Equivalent resistance = RA +RB = R + 2 R = 3 R;

From ohms law I = V/R

I = V/3 R

Now the thermal energy is the power dissipated by the circuit and can be obtained thus;

P = $I^{2}R$

Then,

$P_{A} = (\frac{V}{3R}) ^{2} *2 R\\\\P_{A} = \frac{V^{2} }{9R^{2} } *2R\\\\P_{A} = \frac{2}{9}( \frac{V^{2} }{R}) \\\\P_{B} = (\frac{V}{3R}) ^{2} * R\\\\P_{B} = \frac{V^{2} }{9R^{2} } *R\\\\P_{B} = \frac{1}{9}( \frac{V^{2} }{R})$

Therefore Pa : Pb = 2: 1, this means that the thermal energy dissipated in A would be twice that in B

4 0

3 years ago