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2 years ago

In which of the following substances would convection most likely occur?

Physics

1 answer:

VikaD [51]2 years ago

7 0

Answer:

Air and ice

Explanation:

convection, process by which heat is transferred by movement of a heated fluid such as air or water.

Everyday Examples of Convection:

radiator - A radiator puts warm air out at the top and draws in cooler air at the bottom.

steaming cup of hot tea - The steam you see when drinking a cup of hot tea indicates that heat is being transferred into the air.

ice melting - Ice melts because heat moves to the ice from the air.

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What must an object have in order to exert a gravitational field?

AnnZ [28]

Answer:

power

Explanation:

6 0

3 years ago

The temperature of a room is 77°F what would be the temperature in Celsius scale

anygoal [31]

Formulas change from F to degree C : C = ( F - 32 )/1.8

so we have (77-32)/1.8 = 25 oC

ok done. Thank to me :>

5 0

3 years ago

Cells are considered the smallest part of an organsim that can?

Softa [21]

That can be considered alive.

4 0

3 years ago

A car starts from rest and undergoes an acceleration of 4.0 m/s/s for a time of 5.0 s. What is the final velocity of the car?

Kruka [31]

Answer:

20m/s

Explanation:

acceleration=final velocity-initial velocity/time

4.0m/s²=v m/s-0m/s/5.0sec

5.0sec×4.0m/s²=v m/s-0m/s×5.0m/s/5.0m/s

20m/s=v

7 0

3 years ago

A 39-foot ladder is leaning against a vertical wall. If the bottom of the ladder is being pulled away from the wall at the rate

Viefleur [7K]

Answer:

The rate of change of the area when the bottom of the ladder (denoted by $b$ ) is at 36 ft. from the wall is the following:

$\frac{dA}{dt}|_{b=36}=-571.2\, ft^2/s$

Explanation:

The Area of the triangle is given by $A=h\times b$ where $h=\sqrt{l^2-b^2}$ (by using the Pythagoras' Theorem) and $b$ is the length of the base of the triangle or the distance between the bottom of the ladder and the wall.

The area is then

$A=\sqrt{l^2-b^2}b$

The rate of change of the area is given by its time derivative

$\frac{dA}{dt}=\frac{d}{dt}\left(\sqrt{l^2-b^2}\cdot b\right)$

$\implies \frac{dA}{dt}=\frac{d}{dt}\left(\sqrt{l^2-b^2}\right)\cdot b+\frac{db}{dt}\cdot\sqrt{l^2-b^2}$

$\implies\frac{dA}{dt}=\frac{1}{2\sqrt{l^2-b^2}}\frac{d}{dt}(l^2-b^2)\cdot b+\sqrt{l^2-b^2}}\cdot \frac{db}{dt}$ Product rule

$\implies\frac{dA}{dt}=-\frac{1}{2\sqrt{l^2-b^2}}\cdot 2\cdot b^2\cdot \frac{db}{dt}+\sqrt{l^2-b^2}}\cdot \frac{db}{dt}$ Chain rule

$\implies\frac{dA}{dt}=-\frac{1}{\sqrt{l^2-b^2}}\cdot b^2\cdot \frac{db}{dt}+\sqrt{l^2-b^2}}\cdot \frac{db}{dt}$

$\implies\frac{dA}{dt}=\frac{db}{dt}\left(-\frac{1}{\sqrt{l^2-b^2}}\cdot b^2+\sqrt{l^2-b^2}}\right)$

In here we can identify $b=36\, ft$ , $l=39$ and $\frac{db}{dt}=8\,ft/s$ .

The result is then

$\frac{dA}{dt}=8\left(-\frac{1}{\sqrt{39^2-36^2}}\cdot 36^2+\sqrt{39^2-36^2}}\right)=-571.2\, ft^2/s$

3 0

3 years ago