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yulyashka [42]
4 years ago
15

20 Point Offer for Full Answer.

Physics
1 answer:
Fantom [35]4 years ago
4 0
I think it is number 4 because he is putting force on the chair but the chair is not exerting force on him
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Why are very high temperatures and pressures required for fusion to occur?
Ber [7]

Explanation:

to overcome the repulsion between the protons in the nuclei that join

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3 years ago
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What are the applications of electromagnetic waves​
Fittoniya [83]

Answer:They are used to transmit short or long or FM wavelength radio waves. They are used to transmit TV or telephone or wireless signals and energies. They are responsible for the transmission of energy in the forms of microwaves, visible light, infrared radiation, ultraviolet light, gamma rays and also X-rays.

Explanation:

4 0
4 years ago
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What is the index of refraction in quartz if light travels at 2.0567 x 108m/s when in quartz?
Gnesinka [82]

Index of refraction of a substance =

(speed of light in vacuum) / (speed of light in the substance)

Index in quartz = (2.9979 x 10⁸ m/s) / (2.0567 x 10⁸ m/s)

<em>Index =  1.4576 </em> (no units)

7 0
3 years ago
A woman wears bifocal glasses with the lenses 2.0 cm in front of her eyes. The upper half of each lens has power-0.500 diopter a
saveliy_v [14]

Answer:

q = -2 m  and  q = -0.5 m

Explanation:

For this exercise we must use the equation of the optical constructor

        1 / f = 1 / p + 1 / q

where f is the focal length, p and q are the distance to the object and the image, respectively

Let's start with the far vision point, in this case the power of the lens is

        P = -0.5D

power is defined as the inverse of the focal length in meter

      f = 1 / D

      f = -1 / 0.5

      f = - 2m

the object for the far vision point is at infinity p = infinity

     1 / f = 1 / p + i / q

      1 / q = 1 / f - 1 / p

      1 / q = -1/2 - 1 / ∞

       q = -2 m

The sign indicates that the image is on the same side as the object

Now let's lock the near view point

D = +2.00 D

f = 1 / D

f = 0.5m

the near mink point is p = 25 cm = 0.25 m

        1 / f = 1 / p + 1 / q

        1 / q = 1 / f - 1 / p

        1 / q = 1 / 0.5 - 1 / 0.25

        1 / q = -2

        q = -0.5 m

the sign indicates that the image is on the same side as the object in front of the lens

8 0
4 years ago
4. An object is thrown from from the ground upward with an initial speed of 3.75 m/s. How long will the object be in the air bef
Natali [406]

Answer:

Explanation:

There's an easy way to answer this and then an easier way. I'll do both since I'm not sure what you're doing this for: physics or calculus. Calculus is the easier way, btw.

Going with the physics version first, here's what we know:

a = -9.8 m/s/s

v₀ = 3.75 m/s

t = ??

That's not a whole lot...at least not enough to directly solve the problem. What we have to remember here is that at the max height of a parabolic path, the final velocity is 0. So we can add that to our info:

v = 0 m/s. Use the one-dimensional equation that utilizes all that info and allows us to solve for time:

v = v₀ +at and filling in:

0 = 3.75 + (-9.8)t and

-3.75 = -9.8t so

t = .38 seconds. This is how long it takes to get to its max height. Another thing we need to remember (which is why calculus is so much easier!) is that at the halfway point of a parabolic path (the max height), the object has traveled half the time it takes to make the whole trip. In other words, if .38 is how long it takes to go halfway, then 2(.38) is how long the whole trip takes:

2(.38) = .76 seconds. Now onto the calculus way:

The position function is

s(t)=-4.9t^2+3.75t The first derivative of this is the velocity function and, knowing that when the velocity is 0, the time is halfway gone, we will find the velocity function and then set it equal to 0 and solve for t:

v(t) = -9.8t + 3.75 and

0 = -9.8t + 3.75 and

-3.75 = -9.8t so

t = ,38 and multiply that by 2 to find the time the whole trip took:

2(.38) = .76 seconds.

6 0
3 years ago
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