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3 years ago

NaCl + CaF2 → NaF +CaCl2

1 answer:

5 0

The answer is C. 2, 1, 2, 1
This way both sides of the reaction have the same amount of atoms of each element:
Na = 2 atoms
Cl = 2 atoms
Ca = 1 atom
F = 2 atoms
following the law of conservation of mass which says the mass remains constant, it can't be added or removed

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What phenomena provides evidence of electric fields in the atmosphere

diamong [38]

The phenomena of atmospheric electricity are of three kinds. ..... In the Earth-ionosphere cavity, the electric field and conduction current in the lower atmosphere

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3 years ago

A package of aluminum foil contains 50. Ft2 of foil, which weighs approximately 7.0 oz . Aluminum has a density of 2.70 g/cm3. W

kumpel [21]

We know density = Mass / Volume

So Volume = Mass/Density

Volume = Area * Thickness

$Area = 50 ft^2 = 4.645152 m^2\\ \\Mass = 7 oz = 0.198447 kg\\ \\Density = 2.70 g/cm^3 = 2700 kg/m^3\\ \\Substituting \\ \\4.645152 *t = \frac{0.198447}{2700} \\ \\t = 1.58*10^{-5}m = 1.58*10^{-2}mm$

So the approximate thickness of the foil in millimeters = $1.58*10^{-2}mm$

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4 years ago

A rock of mass 200 g is attached to a 0.75 m long string and swung in a vertical plane.

Ainat [17]

Hello!

a) Assuming this is asking for the minimum speed for the rock to make the full circle, we must find the minimum speed necessary for the rock to continue moving in a circular path when it's at the top of the circle.

At the top of the circle, we have:

- Force of gravity (downward)

*Although the rock is still connected to the string, if the rock is swinging at the minimum speed required, there will be no tension in the string.

Therefore, only the force of gravity produces the net centripetal force:

$\Sigma F = F_g\\\\F_c = F_g\\\\\frac{mv^2}{r} = mg$

We can simplify and rearrange the equation to solve for 'v'.

$\frac{v^2}{r} = g\\\\v^2 = gr\\\\v = \sqrt{gr}$

Plugging in values:

$v = \sqrt{9.8 * 0.75} = \boxed{2.711 m/s^}$

b)
Let's do a summation of forces at the bottom of the swing. We have:
- Force due to gravity (downward, -)

- Tension force (upward, +)

The sum of these forces produces a centripetal force, upward (+).

$\Sigma F = T - F_g\\\\F_c = T - F_g\\\\\frac{mv^2}{r} = T - mg$

Rearranging for 'T":
$T = \frac{mv^2}{r} + mg\\\\$

Plugging in the appropriate values:
$T = \frac{(0.2)(2.711^2)}{(0.75)} + 0.2(9.8) = \boxed{3.92 N}$

5 0

2 years ago

Read 2 more answers

The common value for the speed of light in a vacuum is:

OLEGan [10]

The common value for “Speed of light in vacuum” is $\bold{3 \times 10^{8}}$ metre per second.

Answer: Option b

Solution:

Speed of light can be defined as the speed with which light waves propagate in different medium. In vacuum, speed of light is 186,282 miles per second or 299,792 km/s which is rounded off as $3 \times 10^{8} \mathrm{m} / \mathrm{s}$ .

“Speed of light in vacuum” is a universal constant and usually represented by ‘c’. Light waves travels at a speed of $3 \times 10^{8}$ metre per second in vacuum.

5 0

4 years ago

Do frictional forces act in the same direction or in the opposite direction to the applied force?

Evgesh-ka [11]

Frictional forces act in the direction opposite to the MOTION. That direction could be the same OR opposite to applied force.

-- If you push a loaded heavy wagon from behind, trying to get it going faster, friction is acting against you, opposite to your force.

-- If you push a loaded rolling heavy wagon from in front, trying to make it slow down, friction is acting with you, in the same direction as your force.

-- Opposite to the motion both times.

3 0

3 years ago

__NaCl + __CaF2 → __NaF +__CaCl2

NaCl + CaF2 → NaF +CaCl2