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3 years ago

What 2 kinds of substances does convection occur ?

Physics

1 answer:

ch4aika [34]3 years ago

4 0

Liquids and Gases

Explanation:

Convection is a form of heat transfer that is predominant in liquids and gaseous substances. This form of heat transfer is driven by density differences between gases and liquids.

Convection involves the actual movement of the particles of a medium.
Boiling of food is clinical example of convection in liquids. Hot part of the food in contact with the heat source becomes less dense and more buoyant. They rise to the top of the medium and are replace by the denser and colder part of the food.
Land and sea breeze is an example of convection in gases. The land warms the air around it during the day. It is hotter and less dense. The air mass moves to replace the ones on the sea where the air is relatively cold due to high specific heat capacity of water.
The reverse process occurs at night.

Learn more:

Heat transfer from the sun brainly.com/question/1140127

#learnwithBrainly

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Alpha particles, each having a charge of +2e and a mass of 6.64 ×10-27 kg, are accelerated in a uniform 0.50 T magnetic field to

sergij07 [2.7K]

Answer:

$KE=1.2036\times 10^{-12}\ J$

Explanation:

Given:

charge on the alpha particle, $q=2e=3.2\times 10^{-19}\ C$

mass of the alpha particle, $m=6.64\times 10^{-27}\ kg$

strength of a uniform magnetic field, $B=0.5\ T$

radius of the final orbit, $r=0.5\ m$

<u>During the motion of a charge the magnetic force and the centripetal forces are balanced:</u>

$q.v.B=m.\frac{v^2}{r}$

$m.v=q.B.r$

where:

v = velocity of the alpha particle

$v=\frac{q.B.r}{m}$

$v=\frac{3.2\times 10^{-19}\times 0.5\times 0.5}{6.64\times 10^{-27}}$

$v=1.2048\times 10^{7}\ m.s^{-1}$

Here we observe that the velocity of the aprticle is close to the velocity of light. So the kinetic energy will be relativistic.

<u>We firstly find the relativistic mass as:</u>

$m'=\frac{1}{\sqrt{1-\frac{v^2}{c^2} } } \times m$

$m'=\frac{6.64\times 10^{-27}}{\sqrt{1-\frac{(1.2048\times 10^7)^2}{(3\times 10^8)^2} } }$

$m'=6.6533\times10^{-27}\ kg$

now kinetic energy:

$KE=m'.c-m.c$

$KE=6.6533\times 10^{-27}\times (3\times 10^8)^2-6.64\times 10^{-27}\times (3\times 10^8)^2$

$KE=1.2036\times 10^{-12}\ J$

6 0

3 years ago

4. Which of the following would be a good reference point to describe the motion of a dog?

saul85 [17]

ANOTHER RUNNING DOG

Explanation:

In the given question it is to find a suitable reference point to describe the motion of dog. Here I could suggest that it is better to compare the dog with another running dog to create the relative speed difference to get a reliable motion variation.

Because the motion of dog is in the linear with respect to the another dog and to the acceleration produced by the dog in the required interval is easy to calculate with respect to another dog which is already in motion.

Hence, I suggest that Motion of dog can be analysed better by analyse the motion variation of dog with another dog running.

4 0

2 years ago

Question 2 The gravitational force between two objects with identical masses that are 10 m apart, is 2.67 x10-10 N. To the neare

xxMikexx [17]

Answer 888990,0 kg

Explanation:

3 0

2 years ago

You move a 25 N object 5 meters. How much work did you do ?

olga55 [171]

The answer is 125 Joules

The first thing to take note of is the work equation: W=F×D

Since we already have our force and our distance that will help make this problem easier.

So, W=25*5

W=125

Therefore, our answer is 125 Joules since work is measured in joules

Hope this helped!! :)

3 0

3 years ago

What is the voltage across each resistor?

kogti [31]

Answer:

see solution below

Explanation:

The given resistors are connected in series.

Equivalent resistance in series = 30 + 55 + 15

Equivalent resistance in series Rt = 100 ohms

Since the potential difference in the circuit = 36V

Get the current in the circuit first

I = V/Rt

I = 36/100

I = 0.36A

Get the voltage across 30ohms resistor;

V30 = 0.36 * 30

V30 = 10.8volts

Hence the voltage across the 30ohms resistor is 10.8volts

Get the voltage across 55ohms resistor;

V55 = 0.36 * 55

V55 = 19.8volts

Hence the voltage across the 55ohms resistor is 19.8volts

Get the voltage across 15ohms resistor;

V15 = 0.36 * 15

V15 = 5.4volts

Hence the voltage across the 15ohms resistor is 5.4volts

4 0

2 years ago