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3 years ago

9

B) What are the only two sources of energy that produce all the energy we use on Earth? What form

1 answer:

Zina [86]3 years ago

4 0

Answer:

Solar and nuclear power generate more than 99 percent of our civilization's energy. Every other important source of energy is a combination of these two. The majority of them are solar in nature. We discharge previously collected solar energy when we burn wood.

and

Nuclear energy, fossil energy (oil, coal, and natural gas), and renewable energy (wind, solar, geothermal, and hydropower) are all examples of primary energy sources.

Explanation:

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11. A 3.8 kg object is lifted 12 meters. Approximately how much work is performed during the lifting?

Marianna [84]

I found the answer for you if u need any help ask anytime!

3 0

3 years ago

Optical tweezers use light from a laser to move single atoms and molecules around. Suppose the intensity of light from the tweez

katrin [286]

Answer:

a= 4.4×10 m/s^2

Explanation:

pressure P = E/c

Where, E = 100 W/m^2 intensity of light

c= speed of light = 3×10^8 m/s

P = 1000/ 3×10^8

P = 3.33×10^(-6) Pa

Force F = P×A

P is the pressure and c= speed of light

F = 3.33×10^{-6}×6.65×10(-29)

= 2.22×10^{-6}

acceleration a = F/m = 2.22×10^{-6}/ 5.10×10^{-27}

a= 4.4×10 m/s^2

4 0

3 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

3 years ago

A crane lifts a load of 15000N to a height 40m in 50 seconds. Calculate the power of the crane

Nataly [62]

Answer:

P = 12000 W

Explanation:

General data:

F = 15000 N
d = 40 m
t = 50 s
P = ?

Work is force times unit of distance. So in order to calculate the power we must first calculate the work.

Formula:

$\boxed{\bold{W=\frac{F}{d}}}$

Replace and solve

$\boxed{\bold{W=\frac{15000\ N}{40\ m}}}$

$\boxed{\bold{W=600000\ J}}$

once the work is found, we proceed to find the power according to the formula:

$\boxed{\bold{P=\frac{W}{t}}}$

$\boxed{\bold{P=\frac{600000\ J}{50\ s}}}$

$\boxed{\boxed{\bold{P=12000\ W}}}$

The power of the crane is <u>12000 Watts.</u>

Greetings.

6 0

2 years ago

Which statements about the two fossil images are correct?

tangare [24]

What fossil images, there are no pictures attached.

5 0

3 years ago

Read 2 more answers