Distinguish between velocity and acceleration

If the current in a wire is directed upward, what is the direction of the magnetic field produced by the current?

Valentin [98]

Answer:

B. counterclockwise

Explanation:

We can solve the problem by using the right-hand rule:

- put your thumb finger of the right hand in the same direction of the current in the wire (upward)

- wrap the other fingers around the thumb

- the direction of the other fingers will give the direction of the magnetic field lines

By doing these steps, we see that the other fingers form concentric circles in a counterclockwise direction (seen from above), so this is the direction of the magnetic field lines.

4 0

3 years ago

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For heat transfer purposes, an egg can be considered to be a 5.5-cm-diameter sphere having the properties of water. An egg that

Harrizon [31]

Answer:

The time taken is $t = 40007 sec$

Explanation:

From the question we are told that

The diameter of the egg is $d_e = 5.5cm = \frac{5.5}{100} = 5.5*10^{-2}m$

The initial temperature of egg the $T_e = 4.3^{o}C$

The temperature of the boiling water $T_b = 100^oC$

The heat transfer coefficient is $H = 800 W/m^2 \cdot K$

The final temperature is $T_e_f = 74^oC$

The thermal conductivity of water is $k = 0.607 W/m^oC$

The diffusivity of the egg $\alpha = 0.146 * 10^{-6} m^2 /s$

Using one term approximation

We have the

$\frac{T_e_f - T_b}{T_e - T_b} = Ae^{-\lambda ^2 \tau}$

The radius is $r = \frac{5.5*10^ {-2}}{2} =2.75*10^{-2}m$ Note that this radius is approximation to that of a real egg

Now we need to obtain the Biot number which help indicate the value of $A \ and \ \lambda$ to use in the above equation

The Biot number is mathematically represented as

$Bi = \frac{H r}{k}$

Substituting values

$Bi = \frac{800 * 2.75 *10^{-2}}{0.607}$

$= 36.24$

So for this value which greater than 0.1 the coefficient $\lambda_1 \ and \ A_1$ is

$\lambda = 3.06632$

$A = 1.9942$

Substituting this into equation 1 we have

$\frac{74- 100}{4.3 - 100} = 1.9942 e^{-(3.0632^2) \tau}$

$0.2717= 1.9942 e^{-(3.0632^2) \tau}$

$0.2717= 1.9942 e^{-9.383 \tau}$

$0.13624 = e^{-9.383 \tau}$

Taking natural log of both sides

$-1.993 = -9.383\ \tau$

$\tau = 0.2124$

The time required for the egg to be cooked is mathematically represented as

$t = \frac{\tau r^2}{\alpha }$

substituting value is

$= \frac{0.2124 * 2.75 *10^{-2}}{0.146 *10^{-6}}$

$t = 40007 sec$

8 0

3 years ago

What do you mean by the statement relative density of gold is 19.3

sergey [27]

The relative density of gold is 19.3 it means the ratio obtained by dividing the density of gold by water at temp of 4 degree celcius is 19.3

8 0

3 years ago

HELP ASAP PLEASEEEEEEEEEEEE

ira [324]

It's the second graph!
it's the only one with a negative gradient.
so the temperature of the ball will fall in water as it looses its heat.

activate windows,:-P

8 0

4 years ago

Which planet has completed less than one orbit of the sun in the last 100 years?

OlgaM077 [116]

Since Pluto is no longer considered a planet, the correct answer would be Neptune. It is eight and farthest known planet of the Solar system. Orbital period of planet Neptune is 168 years. So planet Neptune has completed less than one orbit around the Sun in the last 100 years.

6 0

3 years ago

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