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3 years ago

What does density have to do with heat?

2 answers:

8 0

If you take a fluid (i.e. air or water) and heat it, the portion that is heated usually expands. The same mass takes up more volume and as a consequence the heated portion becomes less dense than the portion that is not heated.

Vadim26 [7]3 years ago

7 0

Cooling a substance causes molecules to slow down and get slightly closer together, occupying a smaller volume that results in an increase in density. Hot water is less dense and will float on room-temperature water. Cold water is more dense and willsink in room-temperature water.

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Single Replacement: HCI + Zn

Kay [80]

During a single replacement, the Zn and H will switch places. That means the product formed will be ZnCl and H2.

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3 years ago

Two resistors have resistances R(smaller) and R(larger), where R(smaller) < R(larger). When the resistors are connected in se

ASHA 777 [7]

Answer:

R = 9.85 ohm , r = 0.85 ohm

Explanation:

Let the two resistances by r and R.

when they are connected in series:

V = 12 V

i = 1.12 A

The equivalent resistance when they are connected in series is

Rs = r + R

So, By using Ohm's law

V = i Rs

Rs = V / i = 12 / 1.12 = 10.7 ohm

R + r = 10.7 ohm .... (1)

When they are connected in parallel:

V = 12 V

i = 9.39 A

The equivalent resistance when they are connected in parallel

$R_{p}=\frac{R+r}{rR}$

So, By using Ohm's law

V = i Rp

Rp = V / i = 12 / 9.39 = 1.28 ohm

$\frac{R+r}{rR}=1.28$ .... (2)

by substituting the value of R + r from equation (1) in equation (2), we get

r R = 8.36 ..... (3)

$R-r = \sqrt{\left ( R+r \right )^{2}-4rR}$

$R-r = \sqrt{\left ( 10.7 \right )^{2}-4\times 8.36}=9$ ..... (4)

By solvng equation (1) and (4), we get

R = 9.85 ohm , r = 0.85 ohm

8 0

3 years ago

Why is tornadoes hitting the east coast of the USA?

OLga [1]

Answer:

The outbreak of tornadoes that tore across the Gulf and the East Coast Tuesday and Wednesday was unusual for two reasons. For one thing, the severe weather encompassed a significant swath of the country. For another, winter is the least likely time for tornadic thunderstorms.

Explanation:

And yet tornadoes are an expected part of life in the United States—especially in the multi-state area known as Tornado Alley. (Florida, too, sees a disproportionately high number of tornadoes, because of its frequent thunderstorms.) The United States gets more tornadoes, by far, than any other place on the planet. It averages about 1,250 twisters a year. Canada, which sees about 100 tornadoes per year, is a “distant second,” according to the National Centers for Environmental Information.

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3 years ago

Sarah, whose mass is 40 kg, is on her way to school after a winter storm when she accidentally slips on a patch of ice whose coe

RideAnS [48]

Sarah's acceleration is $-0.49 m/s^2$