All categories

3 years ago

Help!!!!

1 answer:

3 0

1. For the first one if it doesn't shatter then it is hard.
2. We sould consider that room temperature is usuall<span>y from 18°C (64°F) to 23°C (73°F) and since the melting point of the substance is 40˚C the substance is liquid, because is melting point not an evaporation point it just melts from solid to liquid.
3. Well, in this one we have to consider that a chemical change it change the thing completely. So in this case is baking a cake because the products make the cake stop being them self and created something else.
4. It tends to have low reactivity. This is because viscosity means something like honey very sticky<span> ,</span> density is how hard it is and lastly the conductivity I would believe is to pass electricity or current.
5. It is a physical change because the evaporated water transforms again into water and then fall as rain, snow or ice.
Hope it helped <3</span>

You might be interested in

A thin, metallic spherical shell of radius 0.347 m0.347 m has a total charge of 7.53×10−6 C7.53×10−6 C placed on it. A point cha

USPshnik [31]

Answer:

E = 12640.78 N/C

Explanation:

In order to calculate the electric field you can use the Gaussian theorem.

Thus, you have:

$\Phi_E=\frac{Q}{\epsilon_o}$

ФE: electric flux trough the Gaussian surface

Q: net charge inside the Gaussian surface

εo: dielectric permittivity of vacuum = 8.85*10^-12 C^2/Nm^2

If you take the Gaussian surface as a spherical surface, with radius r, the electric field is parallel to the surface anywhere. Then, you have:

$\Phi_E=EA=E(4\pi r^2)=\frac{Q}{\epsilon_o}\\\\E=\frac{Q}{4\pi \epsilon_o r^2}$

r can be taken as the distance in which you want to calculate the electric field, that is, 0.795m

Next, you replace the values of the parameters in the last expression, by taking into account that the net charge inside the Gaussian surface is:

$Q=7.53*10^{-6}C+3.65*10^{-6}C=1.115*10^{-5}C$

Finally, you obtain for E:

$E=\frac{1.118*10^{-5}C}{4\pi (8.85*10^{-12C^2/Nm^2})(0.795m)^2}=12640.78\frac{N}{C}$

hence, the electric field at 0.795m from the center of the spherical shell is 12640.78 N/C

3 0

3 years ago

What Converts sound to a signal in a telephone

Irina-Kira [14]

The part you talk into, that converts the sound of your voice
into an electrical signal, is a tiny microphone.

-- The sound waves from your voice are ripples in the air.

-- In most microphones, there's a tiny coil of wire hanging
between the ends of a tiny magnet.

-- When the ripples in the air hit the little coil of wire, they
make it vibrate (wiggle) slightly.

-- When a coil of wire wiggles in the field of a magnet,
a current flows in the wire.

There's your electrical signal !

6 0

3 years ago

An object of mass 30 kg is in free fall in a vacuum where there is no air resistance. Determine the acceleration of the object.

velikii [3]

Answer:

In free fall, mass is not relevant and there's no air resistance, so the acceleration the object is experimenting will be equal to the gravity exerted. If the object is falling on our planet, the value of gravity is approximately 9.81ms2 .

7 0

3 years ago

Why is salt water a better conductor of electricity than river water?

Tamiku [17]

Answer: The conductivity of water depends on the concentration of dissolved ions in solution. ... This is because the Sodium Chloride salt dissociates into ions. Hence sea water is about a million times more conductive than fresh water.

6 0

3 years ago

A new landowner has a triangular piece of flat land she wishes to fence. Starting at the first corner, she measures the first si

Lera25 [3.4K]

Answer:

Length of third side = 3.97m

Explanation:

First of all, let we draw the triangle from the given information assuming our first corner is A. second corner is B and third corner is C.

From A-B we have distance = 5.5m = Say it c

From B-C we have distance = 4.3m = Say it a

From A-C we have distance = ? = Say it b which we have to find out.

Using the Law of Cosines: The square of the unknown side equals to the sum of squares of other 2 sides and subtracting 2*(Product of other sides)*(Cos(Angle opposite to the unknown side)

For our case it is:

b² = a² + c² - 2acCos(B) - Say it equation 1

From the attached triangle you may see that, a & c are our known sides and B is the angle opposite to the side b.

There values are:

a = 4.3m; c = 5.5m ; Angle B = 0.8 rad = 0.8 * 57.3 = 45.84 degrees where 1 rad = 57.3 degrees

Now by putting the respectve values in equation 1 we have:

b² = (4.3)² + (5.5)² - 2*4.3*5.5*Cos(45.84)

b² = 18.49 + 30.25 - 32.95

b² = 15.79

b = √15.79

b = 3.97m

Thus the length of third side is 3.97m.

PS: The picture of triangle is being attached for yours understanding.

6 0

3 years ago