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Juli2301 [7.4K]

3 years ago

6

Carlos attempts to get a refrigerator magnet to stick on the S end of a bar magnet. He is unable to do so and states that the ba

r magnet is broken. Evaluate his argument: is this correct or incorrect? Explain.

1 answer:

zalisa [80]3 years ago

4 0

Answer:

It is incorrect.

Explanation:

Refrigerator magnets are actually multiple layers of magnets, and they are stacked using opposite polarities, so the south end of the magnet might be under a north, so if he puts the magnet on its side it will probably attract.

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HELP PLEASE 20 ;OINTS

77julia77 [94]

I’m pretty sure it’s C.

7 0

3 years ago

A person yells across a canyon and hears an echo 2.5 seconds later. The air temperature is 21°C. How far away is the canyon wall

Alchen [17]

Answer: The canyon wall is 850 m away from the person

Explanation:

Well, the speed of sound $V$ in air at $21 \° C$ is defined as $343.60 m/s$ , this can be calculated by the following equation:

$V=\sqrt{\frac{\gamma R T}{M}}$ (1)

Where:

$\gamma=1.4$ is the Heat capacity ratio for air

$R=8.314 J/mol.K$ is the Universal Gas constant

$T=21 \° C+273.15=294.15 K$ is the temperature in Kelvin

$M=0.029 kg/mol$ is the air molar mass

$V=\sqrt{\frac{(1.4)(8.314 J/mol.K)(294.15 K)}{0.029 kg/mol}}$

$V=343.60 m/s$ (2)

Now that we know the speed of sound, we can use the following equation to find the distance between the person and the canyon wall:

$V=\frac{d}{t}$ (3)

Where:

$d$ is the distance between the person and the canyon wall

$t=2.5 s$ is the time it takes to the sound wave to travel from the person and then go back

Isolating $d$ :

$d=V.t$ (4)

$d=(343.60 m/s)(2.5 s)$ (5)

Finally:

$d=850 m$

7 0

3 years ago

A car travelled a distance of 200 m with initial velocity of 216 km/hr. Calculate the acceleration

pogonyaev

Answer:

$a = 16\ m/s^2$

Explanation:

When the velocity changes uniformly, the object has a constant acceleration. The acceleration, the velocities, and the distance are related by the equation:

$v_f^2=v_o^2+2ax$

Where:

vf = final velocity

vo = initial velocity

a = acceleration

x = distance

Solving for a:

$\displaystyle a=\frac{v_f^2-v_o^2}{2x}$

The car travels a distance of x=200 m and the velocities are:

vo = 216 Km/h

vf = 360 Km/h

Both velocities must be converted to meters by seconds.

vo = 216 Km/h *1000/3600 = 60 m/s

vf = 360 Km/h *1000/3600 = 100 m/s

The acceleration is:

$\displaystyle a=\frac{100^2-60^2}{2*200}$

$\displaystyle a=\frac{10000-3600}{400}$

$\displaystyle a=\frac{6400}{400}$

$\mathbf{a = 16\ m/s^2}$

7 0

3 years ago

What causes convection currents, and what do they do?

frez [133]

Answer:

Convection currents are the result of different heating. Lighter material (warm) rises while heavier (cold) material sinks. This movement of the materials is what causes convection currents! (BTW, it happens in water, in the atmosphere, and in the mantle of Earth!

Explanation:

I hope this helps a little! :)

6 0

3 years ago

Explain one way the water cycle affects climate. Use complete sentences.

Reika [66]

When water vaporizes into the air, it becomes humid out.

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3 years ago