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3 years ago

Can you help me? Thanks! 10+ points!

Physics

2 answers:

kykrilka [37]3 years ago

7 0

If u need any other help I’d help ! Honestly the person above me answered but feel free to message me if u need help ! I don’t really need the points !

Elis [28]3 years ago

4 0

Explanation:

velocity: average velocity equals Displacement /change in time.

Kinetic energy: K=1/2mv^2 (m = Mass) ( v = Velocity).

speed using the kinetic energy is also KE =1/2mv^2

(M in Kg) (V in m/s)

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A metal block has a mass of 5 grams and a volume of 1 cm3. What is the density of a piece of the same identical metal but with a

Fynjy0 [20]

Answer:

ρ = Mass / Volume definition of density

ρ = 5 g / 1cm^3 = 5 g / cm^3

Since the other object is made of the same metal its density is the same:

ρ = 5 g/cm^3

6 0

2 years ago

An electron is accelerated from rest through a potential difference. After acceleration the electron has a de Broglie wavelength

Vladimir [108]

Answer:

3x10⁴v

Explanation:

Using

Wavelength= h/ √(2m.Ke)

880nm = 6.6E-34/√ 2.9.1E-31 x me

Ke= 6.6E-34/880nm x 18.2E -31.

5.6E-27/18.2E-31

= 3 x 10⁴ Volts

4 0

3 years ago

Lasers are now used in eye surgery. Given the wavelength of a certain laser is 514 nm and the power of the laser is 1.1 W, how m

Leno4ka [110]

Answer: $1.593*10^{17} photons$ released if the laser is used 0.056 s during the surgery

Explanation:

First, you have to calculate the energy of each photon according to Einstein's theoty, given by:

$E =\frac{hc}{\lambda}$

Where $\lambda$ is the wavelength, $h$ is the Planck's constant and $h$ is the speed of light

$h = 6.626*10^{-34} \frac{m^{2} kg }{s}$ -> Planck's constant

$c = 3*10^{8} \frac{m}{s}$ -> Speed of light

So, replacing in the equation:

$E =\frac{ 6.626*10^{-34} \frac{m^{2} kg }{s}*3*10^{8} \frac{m}{s}}{514*10^-9 m}$

Then, the energy of each released photon by the laser is:

$E = 3.867*10^{-19} \frac{J}{photons}$

After, you do the inverse of the energy per phothon and as a result, you will have the number of photons in a Joule of energy:

$\frac{1}{3.867*10^{-19}} = 2.586*10^{18} \frac{photons}{J}$

The power of the laser is 1.1 W, or 1.1 J/s, that means that you can calculate how many photons the laser realease every second:

$2.586*10^{18}\frac{photons}{J} * 1.1 \frac{J}{s} = 2.844*10^{18} \frac{photons}{s}$

And by doing a simple rule of three, if $2.844*10^{18} photons$ are released every second, then in 0.056 s:

$0.056 s*2.844*10^{18} \frac{photons}{s} = 1.593*10^{17} photons$ are released during the surgery

5 0

3 years ago

HELP PLEASE

melisa1 [442]

answer:

<em>Xi</em><em> </em>+ Xf =10km+30km=60km
$v \times \frac{x}{t}$

4 0

2 years ago

A wrench is used to tighten a spark plug. If the wrench handle is 0.20m and a force of 20N is applied, what is the torque applie

Zanzabum

Torque [Nm] = Force [N] x Force arm [m]

C=F*b=20*0.20=4 Nm

The correct answer is C

4 0

3 years ago