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2 years ago

Can someone please help me?? i’ll give brainilist

Physics

1 answer:

Ksivusya [100]2 years ago

7 0

Probably 90 j but im not sure I haven’t done any work like this in a while

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How are thunderstorms kept alive?

Burka [1]

Answer:

E step leader

Explanation:

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2 years ago

Enter your answer in the provided box. The mathematical equation for studying the photoelectric effect is hν = W + 1 2 meu2 wher

siniylev [52]

Answer:

$v = 4.44 \times 10^5 m/s$

Explanation:

By Einstein's Equation of photoelectric effect we know that

$h\nu = W + \frac{1}{2}mv^2$

here we know that

$h\nu$ = energy of the photons incident on the metal

$W$ = minimum energy required to remove photons from metal

$\frac{1}{2}mv^2$ = kinetic energy of the electrons ejected out of the plate

now we know that it requires 351 nm wavelength of photons to just eject out the electrons

so we can say

$W = \frac{hc}{351 nm}$

here we know that

$hc = 1242 eV-nm$

now we have

$W = \frac{1242}{351} = 3.54 eV$

now by energy equation above when photon of 303 nm incident on the surface

$\frac{1242 eV-nm}{303 nm} = 3.54 eV + \frac{1}{2}(9.1 \times 10^{-31})v^2$

$4.1 eV = 3.54 eV + (4.55 \times 10^{-31}) v^2$

$(4.1 - 3.54)\times 1.6 \times 10^{-19}) = (4.55 \times 10^{-31}) v^2$

$8.96 \times 10^{-20} = (4.55 \times 10^{-31}) v^2$

$v = 4.44 \times 10^5 m/s$

6 0

2 years ago

A 39.3 g glass thermometer reads 22.0oC before it

ratelena [41]

Answer:

44.85C

Explanation:

Let the specific heat of glass thermometer be 0.84 J/g°C

Let the specific heat of water be 4.186 j/g °C

Let the water density be 1kg/L

136 mL of water = 0.136L of water = 0.136 kg of water = 136 g of water

Since the change of temperature on the glass thermometer is 43.6 - 22 = 21.6 C. We can then calculate the heat energy absorbed to it:

$E = m_gc_g \Delta T = 39.3 * 0.84 * 21.6 = 713.06 J$

Assume no energy is lost to outside, by the law of energy conservation, this heat energy would come from water

$E = m_wc_w(T - T_w) = 713.06$

$136*4.186(T - 43.6) = 713.06$

$T - 43.6 = \frac{713.06}{136*4.186} = 1.25$

$T = 1.25 + 43.6 = 44.85C$

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2 years ago

A vehicle is moving with 20m/s towards the east and another is moving 15m/s towards the west

just olya [345]

Answer:

5 m/s

Explanation:

Given that,

A vehicle is moving with 20m/s towards the east and another is moving 15m/s towards the west.

It is assumed to find the resultant velocity of the vehicle. Let east side is positive and west is negative. So,

$v=v_1+v_2\\\\=20+(-15)\\\\=5\ m/s$

Hence, the resultant velocity of the vehicle is equal to 5 m/s.

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2 years ago

A 200.0 g block rests on a frictionless, horizontal surface. It is pressed against a horizontal spring with spring constant 4500

kenny6666 [7]

Answer:

6 m/s

Explanation:

Given that :

mass of the block m = 200.0 g = 200 × 10⁻³ kg

the horizontal spring constant k = 4500.0 N/m

position of the block (distance x) = 4.00 cm = 0.04 m

To determine the speed the block will be traveling when it leaves the spring; we applying the work done on the spring as it is stretched (or compressed) with the kinetic energy.

i.e $\frac{1}{2} kx^2 = \frac{1}{2} mv^2$

$kx^2 = mv^2$

$4500* 0.04^2 = 200*10^{-3} *v^2$

$7.2 =200*10^{-3}*v^{2}$

$v^{2} =\frac{7.2}{200*10^{-3}}$

$v =\sqrt{\frac{7.2}{200*10^{-3}}}$

v = 6 m/s

Hence,the speed the block will be traveling when it leaves the spring is 6 m/s

5 0

3 years ago