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Fynjy0 [20]
3 years ago
11

12. The resistivity of a given wire of cross-sectional

Physics
1 answer:
luda_lava [24]3 years ago
3 0

R = resistivity × (l/A), A = πr^2= πd^2/4

2 =( 4.9 × 10^ -4) * (l/π0.7^2/4)

make l the subject and calculate.

i assumed we are looking for the length if the wire.

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A skydiver of mass 80.0 kg jumps from a slow-moving aircraft and reaches a terminal speed of 50.0 m/s. (a) What is her accelerat
kirill [66]

Answer:

6.22²

Explanation:

Given that

Mass of the skydiver, m = 80 kg

Terminal speed of the skydiver, v(f) = 50 m/s

Speed of the skydiver, v(i) = 30 m/s

Acceleration of the skydiver, a = ?

To solve this, we use the formula

W - k v² = ma, where

W = weight of the skydiver

k = constant

v = speed of the skydiver

m = mass of the skydiver

So, if we substitute the values into it we have

W = mg = 80 * 9.8 = 784 N

784 - k 50² = 80 *0

784 - 2500k = 0

784 = 2500k

k = 0.3136

Now, we use this value of k to find the needed acceleration using the same formula at a speed of 30 m/s

784 - 0.3136 * 30² = 80 * a

784 - 0.3136 * 900 = 80a

784 - 282.24 = 80a

497.76 = 80a

a = 497.76 / 80

a = 6.22 m/s²

Thus, we can conclude that the acceleration when the speed of the skydiver is 30 m/s, is 6.22 m/s²

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3 years ago
The sound wave produced from playing the A key one octave above the "Middle C" on the plano produces a sound wave with a frequen
natita [175]

Answer:

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<u>Pitch</u>- number of wavelengths in a given amount of time.

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Answer:

C. 150 m

Explanation:

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The high and low tides are created because of the combination of effects from the moon's gravitational forces with the sun's gravitational forces that affect the tide as the earth rotates
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Why are concussions a major concern? CER <br> Claim<br> Evidence<br> Reasoning
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Answer:

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