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3 years ago

How do rocks record changes in earths magnetic field

Physics

1 answer:

tino4ka555 [31]3 years ago

7 0

Because there is magnetic rocks. And rocks change through time

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HELP ASAP How are the bars in barred spiral galaxies thought to have formed?

sergey [27]

Answer:

D. slow evolution

Explanation:

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3 years ago

You measure the velocity of a drag racer that accelerates with constant acceleration. You want to plot the data and determine th

Ivenika [448]

Answer:

a) Linear equation

Explanation:

Definition of acceleration

$a=\frac{dv}{dt}\\$

if a=constant and we integrate the last equation

$v(t)=v_{o}+a*t$

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3 years ago

For the graph above, what is the independent variable? What is the dependant variable?

posledela

Time/sec. the x-axis is always the independent variable.

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3 years ago

A carnot heat engine receives 600 kj of heat from a source of unknown temperature and rejects 175 kj of it to a sink at 20°c. de

oee [108]

(b) 71%

The thermal efficiency of a Carnot heat engine is given by:

$\eta = \frac{W}{Q_{in}}$

where

W is the useful work done by the engine

$Q_{in}$ is the heat in input to the machine

In this problem, we have:

$Q_{in}=600 kJ$ is the heat absorbed

$W=600 kJ-175 kJ=425 kJ$ is the work done (175 kJ is the heat released to the sink, therefore the work done is equal to the difference between the heat in input and the heat released)

So, the efficiency is

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(a) $737^{\circ}C$

The efficiency of an engine can also be rewritten as

$\eta = 1-\frac{T_C}{T_H}$

where

$T_C$ is the absolute temperature of the cold sink

$T_H$ is the temperature of the source

In this problem, the temperature of the sink is

$T_C = 20^{\circ}C + 273=293 K$

So we can re-arrange the equation to find the temperature of the source:

$T_H = \frac{T_C}{1-\eta}=\frac{293 K}{1-0.71}=1010 K\\T_H = 1010 K - 273=737^{\circ}C$

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3 years ago

How do elements change as you move down a column in a periodic table? a.the atomic radius decreases b.the number of protons decr

MariettaO [177]

As you move down a column :
* the atomic number increases
* the number of protims increases
* the atomic mass increases
* the electronegativity decreases

4 0

4 years ago

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