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3 years ago

Physics

2 answers:

Shtirlitz [24]3 years ago

7 0

Answer:

Your correct answer is W

Explanation:

Hope this helps :) -Mark Brainiest Please :)

Leto [7]3 years ago

6 0

Answer:

Explanation:

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Veronika [31]

Answer:

Explanation:

3 0

3 years ago

Read 2 more answers

În ce raport de mase trebuie amestecate două cantități din același lichid, având temperaturile t1=10 grade Celsius, respectiv t2

Brilliant_brown [7]

Răspuns:

7: 4

Explicaţie:

Formula pentru calcularea cantității de căldură absorbită este exprimată ca;

Q = mc∆t

m este masa substanței

c este capacitatea termică specifică

∆t este schimbarea temperaturii

Conform legii calorimetriei, căldura pierdută de substanța rece = căldura câștigată de substanța fierbinte.

Folosind formula

(mc∆t) rece = (mc∆t) fierbinte

McCw∆tc = MhCw∆th

Deoarece au aceeași capacitate de căldură specifică, se vor anula. Ecuația devine;

Mc∆tc = Mh∆th ...... 1

Pentru apa rece;

∆tc = 45 ° C - 10 ° C

∆tc = 35 ° C

Pentru apa fierbinte:

∆th = 65 ° C - 45 ° C

∆th = 20 ° C

Înlocuiți în ecuația 1;

Mc (35) = Mh (20)

35Mc = 20Mh

Luând raportul dintre masa apei reci și cea fierbinte:

Mh / Mc = 35/20

Mh / Mc = 7/4

Prin urmare, lichidul trebuie amestecat împreună în raportul 7: 4

8 0

3 years ago

Using a horizontal force of 200N,we intend to move a wooden cabinet across a floor at constant velocity.What is the friction for

IgorLugansk [536]

Answer:

-200 N

Explanation:

The cabinet moves at constant velocity, so that means there's no acceleration.

Applying Newton's second law to the cabinet:

∑F = ma

F + 200 = 0

F = -200

The friction force is 200 N in the opposite direction.

8 0

3 years ago

Photoelectric effect:

Lynna [10]

Answer:

A. K = 0.546 eV

B. cooper and iron will not emit electrons

Explanation:

A. This is a problem about photoelectric effect. Then you have the following equation:

$K=h\nu-\Phi=h\frac{c}{\lambda} -\Phi$ (1)

K: kinetic energy of the ejected electron

Ф: Work function of the metal = 2.48eV

h: Planck constant = 4.136*10^{-15} eV.s

λ: wavelength of light = 410nm - 750nm

c: speed of light = 3*10^8 m/s

As you can see in the equation (1), higher the wavelength, lower the kinetic energy. Then, the maximum kinetic energy is obtained with the lower wavelength (410nm). Thus, you replace the values of all variables :

$K=(4.136*10^{-15}eV)\frac{3*10^8m/s}{410*10^{-9}m}-2.48eV\\\\K=0.546eV$

B. First you calculate the energy of the photon with wavelengths of 410nm and 750nm

$E_1=(4.136*10^{-15}eV)\frac{3*10^{8}m/s}{410*10^{-9}m}=3.02eV\\\\E_2=(4.13610^{-15}eV)\frac{3*10^{8}m/s}{750*10^{-9}m}=1.6544eV$

You compare the energies E1 and E2 with the work functions of the metals and you can conclude:

sodium = 2.3eV < E1

cesium = 2.1 eV < E1

cooper = 4.7eV > E1 (this metal will not emit electrons)

iron = 4.5eV > E1 (this metal will not emit electrons)

5 0

3 years ago

The New England Merchants Bank Building in Boston is 152 m high. On windy days it sways with a frequency of 0.15Hz , and the acc

Minchanka [31]

Answer:

See answer below

Explanation:

Hi there,

I'm a bit late with this response, but I attached the work below.

Good luck with physics, have fun!

thanks,

4 0

3 years ago