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strojnjashka [21]

3 years ago

8

A wire with a resistance R is lengthened to 3.07 times its original length by pulling it through a small hole. Find the new resi

stance of the wire after it was stretched.

1 answer:

charle [14.2K]3 years ago

4 0

Explanation:

Below is an attachment containing the solution.

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An astronaut is out in space with an extremely precise timing device measuring the speed of various fast‑moving objects. A laser

Leviafan [203]

Answer and Explanation:

with reference to Einstein's theory of special relativity, the speed of an electromagnetic radiation, here, laser will not change in any inertial frame or remains same irrespective of any change in inertial frame.

Therefore, the speed of light measured in both the cases, i.e., in astronaut's reference frame and spaceship's reference frame will be equal to the speed of light in vacuum, i.e., $3\times 10^{8} m/s$ .

The laser gun's speed in astronaut's reference frame is the same as the speed of the spaceship as it mounted on it, i.e., the speed of the laser gun is 200 million m/s.

The laser gun's speed measured in spaceship's reference frame will be zero, as it is mounted on the spaceship and is stationary in the spaceship's reference frame.

5 0

3 years ago

What are the three symbols used in Ohm's law. Explain what each symbol represents and give the units for each of the variables.

Lerok [7]

Answer:

Step by step explanation:

6 0

2 years ago

Water flowing through a cylindrical pipe suddenly comes to a section of the pipe where the diameter decreases to 86% of its prev

masha68 [24]

Answer:

The speed in the smaller section is $43.2\,\frac{m}{s}$

Explanation:

Assuming all the parts of the pipe are at the same height, we can use continuity equation for incompressible fluids:

$\Delta Q=0$ (1)

With Q the flux of water that is $Av$ with A the cross section area and v the velocity, so by (1):

$A_{2}v_{2}-A_{1}v_{1}=0$

subscript 2 is for the smaller section and 1 for the larger section, solving for $v_{2}$ :

$v_{2}=\frac{A_{1}v_{1}}{A_{2}}$ (2)

The cross section areas of the pipe are:

$A_{1}=\frac{\pi}{4}d_{1}^{2}$

$A_{2}=\frac{\pi}{4}d_{2}^{2}$

but the problem states that the diameter decreases 86% so $d_{2}=0.86d_{1}$ , using this on (2):

$v_{2}=\frac{\frac{\pi}{4}d_{1}^{2}v_{1}}{\frac{\pi}{4}d_{2}^{2}}=\frac{\cancel{\frac{\pi}{4}d_{1}^{2}}v_{1}}{\cancel{\frac{\pi}{4}}(0.86\cancel{d_{1}})^{2}}\approx1.35v_{1}$

$v_{2}\approx(1.35)(32)\approx43.2\,\frac{m}{s}$

5 0

3 years ago

crimeas [40]

Answer

-The magnitude of acceleration during the fall is greater

3 0

3 years ago

A potato and raisins salad has been warmed up to a temperature of 80∘C and let it stand for three minutes. Then one tries a bite

gtnhenbr [62]

Answer:

No. Potatoes will be warmer.

Explanation:

$Q=m\times c\times \Delta T$

where,

Q = heat taken

m = mass of substance

c = specific heat of substance = ?

ΔT = change in temperature

As we are given that the potatoes have a specific heat of 3430 J/(kg⋅∘C) and raisins have a specific heat of 1630 J/(kg⋅∘C). It implies that substance take more heat when higher the value of specific heat i.e more warmer will be the substance. Thus, the potatoes will be more warmer as compared to raisins.

Therefore, No. Potatoes will be warmer.

7 0

3 years ago