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3 years ago

Celina has a water sample that’s contaminated with salt and microorganisms. Which method should she use to purify the water?

Physics

2 answers:

agasfer [191]3 years ago

8 0

Answer: evaporation

Explanation:

The boiling of water till it evaporate allow the salt to remain in the pan and the high temperature kills the microorganisms

She should collect the vapor with a cooking pipe in another container

Dmitry_Shevchenko [17]3 years ago

7 0

Celina should perform the following method to get pure water:

Boil the water in a pan, as the water boils it changes into gas (water vapours) these vapours should be cooled down through the process of condensation which changes gas into liquid form, Through this process germs would be killed due to high temperature and the salt will remain in the pan as salt has higher boiling point than water,

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An all-electric car (not a hybrid) is designed to run from a bank of 12.0 V batteries with total energy storage of 2.30 ✕ 107 J.

AnnyKZ [126]

Answer:

a) $I=733.33\ A$

b) $d=52272.7273\ m$

c) $d'=51948.0519\ m$

Explanation:

Given:

voltage of the battery, $V=12\ V$

energy storage capacity of the battery, $E=2.3\times 10^7\ J$

speed of the car, $v=20\ m.s^{-1}$

power drawn by the car, $P=8.8\ kW$

Now the Current delivered to the motor:

we the relation between the power and electrical current,

$P=V.I$

$8800=12\times I$

$I=733.33\ A$

Distance travelled before battery is out of juice:

we first find the time before the battery runs out,

$t=\frac{E}{P}$

$t=\frac{2.3\times 10^7}{8800}$

$t=2613.636\ s$

Now the distance:

$d=v.t$

$d=20\times 2613.636$

$d=52272.7273\ m$

When the head light of 55 W power is kept on while moving then the power consumption of the car is:

$P'=P+55$

$P'=8800+55$

$P'=8855\ W$

Now the time of operation of the car:

$t'=\frac{E}{P'}$

$t'=\frac{2.3\times 10^7}{8855}$

$t'=2597.4026\ s$

Now the distance travelled:

$d'=v.t'$

$d'=20\times 2597.4025$

$d'=51948.0519\ m$

5 0

3 years ago

A fourth-grade teacher wants to ensure students understand the life cycle process of plants. The teacher decides to incorporate

Annette [7]

Answer:

There are several options that the teacher can use to incorporate the concept into students' understanding.

Explanation:

1. The students can draw all the plants that they know.

2. Children can be asked to bring the flowers to school so that they can identify the plants themselves.

3. The children can plat the flowers in makeshift pots and then take the best plants and transplant them in the garden or elsewhere.

4. The children can take occasional trips and observe and record any changes to the plants.

4. The teacher can ask the students to draw the flowers and emphasize on the productive parts like the stamens, leaves, pistils, stems.

4 0

3 years ago

I’m not sure how to do this

aleksley [76]

Do what?? i know how to do a lot of things to answer but there’s nothing to answer.‍♀️

6 0

3 years ago

17. Suppose you attach the object with mass m to a vertical spring originally at rest, and let it bounce up and down. You releas

insens350 [35]

Answer:

See below ↓

Explanation:

Step 1 : Diagram

In attachment

Step 2

We choose the system to be the spring, the block, and the Earth and it is isolated
We put all the data in the figure we have created and create a zero level (initial height) of the block to be yₓ = 0 and the final position, when it stops and moves upwards again, to be yₙ = -A
No external forces are exerted on the system and no energy comes in or out of the system
Hence,

⇒ ΔE = 0

⇒ Eₙ - Eₓ = 0

⇒ Eₙ = Eₓ

⇒ Kₙ + Uₙ + Pₙ = Kₓ + Uₓ + Pₓ

Final kinetic energy is 0 at the lowest point

⇒ Uₙ + Pₙ = Uₓ + Pₓ

Step 3

Initial potential energy is 0 [zero level = initial height]

⇒ Uₙ + Pₙ = Uₓ

And we know that spring was originally at normal length, so initial spring energy is also 0

⇒ Uₙ + Pₙ = 0

⇒ 1/2kxₙ² + mgyₙ = 0

⇒ 1/2kxₙ² = -mgyₙ

We know xₙ = A and yₙ = -A from the diagram

⇒ 1/2kA² = -mg(-A)

⇒ 1/2kA² = mgA

⇒ [1/2kA = mg]

Step 4

Spring force is given by : F = -kx
Note : x = A

⇒ F = kA

⇒ k = F/A

⇒ Plug 'k' into the equation found at the end of Step 3

⇒ 1/2(F/A)(A) = mg

⇒ 2F = mg

⇒ F = 2mg (a)

Step 5

We know the spring will stop oscillating and be at rest at the new equilibrium position of the system

⇒ F - mg = 0

⇒ F = mg

We know that :

⇒ F = -kx

In the case x = yₙ

⇒ kyₙ = mg

⇒ yₙ = mg/k

⇒ yₙ = 0.25 x 9.8 / -10

⇒ yₙ = -0.245 m

⇒ yₙ = A

⇒ yₙ = 0.245 m (b)

Step 6

v(max) = Aω
v(max) = A√k/m
v(max) = 0.245 x √(10/0.25)
v(max) = 1.55 m/s (c)

8 0

2 years ago

25. Which units would be the most appropriate to use to measure the degree of attraction between two objects due to their mass?

Gnom [1K]

The attraction between two objects is force.
As such, if you don't describe the degree of attraction
in units of force, you're doomed.

Whether to use micronewtons, millinewtons, newtons,
giganewtons, ounces, pounds, or tons, really depends on
the size of the force, which in turn depends on the masses
of the two objects and the distance between them. You'll
want to select the unit that produces the most convenient
number. And of course, you'll want to favor the SI units.

8 0

3 years ago

Read 2 more answers