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3 years ago

12

A horizontal metal bar oriented east-west drops straight down in a location where the earth's magnetic field is due north. as a

result, an emf develops between the ends. which end is positively charged?

1 answer:

amid [387]3 years ago

5 0

Metal bar is aligned along East- West direction and it is dropped vertically down

So its velocity is along -Z direction,

Now the Earth's magnetic field is towards north so its towards +Y direction

now we have formula for force on a moving charge

$F = q(v X B)$

v = - z direction

B = + y direction

now by the above formula

$F = q(v(-k) X B(j))$

$F = qvB (i)$

So force is towards East

so all positive charge is towards East end

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Children's immune systems are very active and excludes them from being a high risk to foodbourne illness.

Alex17521 [72]

Answer:

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8 0

3 years ago

A mole of ideal gas expands at T=27 °C. The pressure changes from 20 atm to 1 atm. What’s the work that the gas has done and wha

Airida [17]

Answer:

The work made by the gas is 7475.69 joules
The heat absorbed is 7475.69 joules

Explanation:

<h3>Work</h3>

We know that the differential work made by the gas its defined as:

$dW = P \ dv$

We can solve this by integration:

$\Delta W = \int\limits_{s_1}^{s_2}\,dW = \int\limits_{v_1}^{v_2} P \ dv$

but, first, we need to find the dependence of Pressure with Volume. For this, we can use the ideal gas law

$P \ V = \ n \ R \ T$

$P = \frac{\ n \ R \ T}{V}$

This give us

$\int\limits_{v_1}^{v_2} P \ dv = \int\limits_{v_1}^{v_2} \frac{\ n \ R \ T}{V} \ dv$

As n, R and T are constants

$\int\limits_{v_1}^{v_2} P \ dv = \ n \ R \ T \int\limits_{v_1}^{v_2} \frac{1}{V} \ dv$

$\Delta W= \ n \ R \ T \left [ ln (V) \right ]^{v_2}_{v_1}$

$\Delta W = \ n \ R \ T ( ln (v_2) - ln (v_1 )$

$\Delta W = \ n \ R \ T ( ln (v_2) - ln (v_1 )$

$\Delta W = \ n \ R \ T ln (\frac{v_2}{v_1})$

But the volume is:

$V = \frac{\ n \ R \ T}{P}$

$\Delta W = \ n \ R \ T ln(\frac{\frac{\ n \ R \ T}{P_2}}{\frac{\ n \ R \ T}{P_1}} )$

$\Delta W = \ n \ R \ T ln(\frac{P_1}{P_2})$

Now, lets use the value from the problem.

The temperature its:

$T = 27 \° C = 300.15 \ K$

The ideal gas constant:

$R = 8.314 \frac{m^3 \ Pa}{K \ mol}$

So:

$\Delta W = \ 1 mol \ 8.314 \frac{m^3 \ Pa}{K \ mol} \ 300.15 \ K ln (\frac{20 atm}{1 atm})$

$\Delta W = 7475.69 joules$

<h3>Heat</h3>

We know that, for an ideal gas, the energy is:

$E= c_v n R T$

where $c_v$ its the internal energy of the gas. As the temperature its constant, we know that the gas must have the energy is constant.

By the first law of thermodynamics, we know

$\Delta E = \Delta Q - \Delta W$

where $\Delta W$ is the Work made by the gas (please, be careful with this sign convention, its not always the same.)

So:

$\Delta E = 0$

$\Delta Q = \Delta W$

7 0

3 years ago

I would like to know why this is the correct answer

Marta_Voda [28]

Answer:

see below

Explanation:

First, the obvious, as you press the gas pedal harder the acceleration goes up as well. Conversely, is you do not press the pedal, you will not accelerate. This determines that is I press the gas pedal, it will CAUSE the car to accelerate. This proves causation.

Now, correlation. The definition of correlation in statistics is any statistical relationship between two random variables or data. This simply means that these two events are connected to one another. A POSITIVE correlation is when two correlated events move in the same direction as one another. I have added a graph to help visualize this. In this problem as the gas is pressed harder, the acceleration increases. If the pressure on the pedal was decreased, then the acceleration also decreases. If the pressure on the pedal is constant, the the acceleration is constant.

I hope this helps!

4 0

3 years ago

What wavelength would a ripple in water have if the frequency is 1.8 Hz and a

Yuki888 [10]

Explanation:

825m/s / 1.8Hz = 458.33m

6 0

2 years ago

Read 2 more answers

1) A plane's velocity increases from 40 m/s to 100 m/s over a 10 second interval. What is the plane's average acceleration for t

Yakvenalex [24]

Answer:

average acceleration = 6 $\frac{m}{s^2}$

Explanation:

Recall that the average acceleration $(a)$ is defined by the change in velocity from an initial velocity $(v_i)$ , to a final velocity $(v_f)$ over the time (t) it took that change to happen. Then, in mathematical terms this is:

$a=\frac{v_f-v_i}{t}$

with our information this becomes:

$a=\frac{v_f-v_i}{t} = \frac{100-40}{10}=6\,\frac{m}{s^2}$

8 0

3 years ago