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4 years ago

15

In 1949, dr. tony allison observed a high frequency of kenyans carrying the sickle cell allele in coastal areas and near lake vi

ctoria, but a lower frequency in the highlands. what did he hypothesize?

1 answer:

Lynna [10]4 years ago

8 0

Dr Tony Allision hypothesize that the sickle cell disease is connected with malaria. The disease carried by the mosquito is more common in coastal area and near Lake Victoria while it is less common in the highlands. He made a further hypothesis that sickle cell disease is common in areas where malaria is also common.

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It represents the amount of speed per time or (x) for speed (y) for time so the slope would be like y/x

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3 years ago

Water flows straight down from an open faucet. The cross-sectional area of the faucet is 2.4 × 10-4m2 and the speed of the water

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To solve this problem it is necessary to apply the continuity equations in the fluid and the kinematic equation for the description of the displacement, velocity and acceleration.

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h = Height

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$A_1 = 2.4*10^{-4} m^2$

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$h = 0.11m$

Replacing at the kinetic equation to find $V_2$ we have,

$v_2 = \sqrt{v_1^2 + 2gh}$

$v_2 = \sqrt{(0.8 m/s)^2 + 2(9.80 m/s2)(0.11 m)}$

$v_2= 1.67 m/s$

Applying the concepts of continuity,

$A_1v_1 = A_2v_2$

We need to find A_2 then,

$A_2= \frac{A_1v_1 }{v_2}$

So the cross sectional area of the water stream at a point 0.11 m below the faucet is

$A_2= \frac{A_1v_1 }{v_2}$

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$A_2= 1.14*10^{-4} m2$

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3 years ago

Two concrete spans of a 380 m long bridge are

Mazyrski [523]

Answer:

4.163 m

Explanation:

Since the length of the bridge is

L = 380 m

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$L_i = \frac{L}{2}=\frac{380}{2}=190 m$

Due to the increase in temperature, the length of each span increases according to:

$L_f = L_i(1+ \alpha \Delta T)$

where

$L_i = 190 m$ is the initial length of one span

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Substituting,

$L_f=(190)(1+(1.2\cdot 10^{-5})(20))=190.0456 m$

By using Pythagorean's theorem, we can find by how much the height of each span rises due to this thermal expansion (in fact, the new length corresponds to the hypothenuse of a right triangle, in which the base is the original length of the spand, and the rise in heigth is the other side); so we find:

$h=\sqrt{L_f^2-L_i^2}=\sqrt{(190.0456)^2-(190)^2}=4.163 m$

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3 years ago