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Y_Kistochka [10]

3 years ago

9

which of the following describes water changing from liqyid to solid, please give me a proof for this question please i really n

eed help

2 answers:

Fittoniya [83]3 years ago

4 0

The answers A, this is because Ice is originally water and when water goes below it's freezing point it turns into ice

navik [9.2K]3 years ago

3 0

The answer is a hope this helps

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2.<br> ___ ___ is the number of wavelengths that pass a given point/second.

atroni [7]

Answer:

frequency tell me if im right

Explanation:

5 0

3 years ago

A 3 kg rock sits on a 0.8 meter ledge. If it is pushed off, how fast will it be going at the bottom?

andrey2020 [161]

As long as it sits on the shelf, its potential energy
relative to the floor is . . .

   Potential energy =    (mass) x (gravity) x (height) =

   (3 kg) x (9.8 m/s²) x (0.8m) = <u>23.52 joules</u> .

If it falls from the shelf and lands on the floor, then it has exactly that
same amount of energy when it hits the floor, only now the 23.52 joules
has changed to kinetic energy.

   Kinetic energy =    (1/2) x (mass) x (speed)²

   23.52 joules = (1/2) x (3 kg) x (speed)²

Divide each side by 1.5 kg :    23.52 m²/s² = speed²

Take the square root of each side: speed = √(23.52 m²/s²) = <em>4.85 m/s </em> (rounded)

6 0

3 years ago

What is the maximum value of the magnetic field at a distance of 2.5 m from a light bulb that radiates 100 W of single-frequency

Anvisha [2.4K]

Answer:

$1.04\times 10^{-7}$ T

Explanation:

$IP$ = Power of the bulb = 100 W

$r$ = distance from the bulb = 2.5 m

$I$ = Intensity of light at the location

Intensity of the light at the location is given as

$I = \frac{P}{4\pi r^{2}}$

$I = \frac{100}{4(3.14) (2.5)^{2}}$

$I$ = 1.28 W/m²

$B_{o}$ = maximum magnetic field

Intensity is given as

$I = \frac{B_{o}^{2}c}{2\mu _{o}}$

$1.28 = \frac{B_{o}^{2}(3\times 10^{8})}{2(12.56\times 10^{-7})}$

$B_{o} = 1.04\times 10^{-7}$ T

7 0

3 years ago

A professor, with dumbbells in his hands and holding his arms out, is spinning on a turntable with an angular velocity. What hap

Olenka [21]

Answer:

<em>His angular velocity will increase.</em>

Explanation:

According to the conservation of rotational momentum, the initial angular momentum of a system must be equal to the final angular momentum of the system.

The angular momentum of a system = $I$ 'ω'

where

$I$ ' is the initial rotational inertia

ω' is the initial angular velocity

the rotational inertia = $mr'^{2}$

where m is the mass of the system

and r' is the initial radius of rotation

Note that the professor does not change his position about the axis of rotation, so we are working relative to the dumbbells.

we can see that with the mass of the dumbbells remaining constant, if we reduce the radius of rotation of the dumbbells to r, the rotational inertia will reduce to $I$ .

From

$I$ 'ω' = $I$ ω

since $I$ is now reduced, ω will be greater than ω'

therefore, the angular velocity increases.

5 0

3 years ago

14. If the spring constant of a simple harmonic oscillator is doubled, by what factor will the mass of the system need to change

klio [65]

Lets se

And

$\\ \rm\Rrightarrow T=2\pi\sqrt{\dfrac{m}{k}}$

$\\ \rm\Rrightarrow \sqrt{k}T=2\pi\sqrt{m}$

So

$\\ \rm\Rrightarrow k\propto m$

If spring constant is doubled mass must be doubled

8 0

2 years ago