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Andrei [34K]
3 years ago
9

Aquatic ecosystems consist of two different layers with respect to light. The photic zone is where light penetrates the water, a

t the surface and a little below. The aphotic zone is where the water is perpetually dark because the light cannot penetrate that deep into the water. The zone depths vary due to salinity and clarity of water.
Which of the following must be true about the organisms living in the aphotic zone?
A.
They have adapted to having no light for an energy source and are able to live in dark and cold areas.
B.
They all must move to the surface of the water once a day to receive adequate light energy.
C.
They have all become fluorescent so they can all be seen by one another.
D.
Many organisms have not been able to survive in the cold, dark waters, so population is low.
Physics
2 answers:
Lostsunrise [7]3 years ago
7 0

Answer: a

Explanation: it talks about how they live without that much light

Ivahew [28]3 years ago
4 0

Answer:

Answer A

Explanation:

Did the study island lesson

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Two forces act on a 6.00-kg object. One of the forces is 10.0 N. If the object accelerates at 2.00 m/s2
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Given :

Two forces act on a 6.00-kg object. One of the forces is 10.0 N.

Acceleration of object 2 m/s².

To Find :

The greatest possible magnitude of the other force.\

Solution :

Let, other force is f.

So, net force, F = 10 + f.

Now, acceleration is given by :

a=\dfrac{F}{mass}\\\\a= \dfrac{10+f}{6}\\\\\dfrac{10+f}{6}=2\\\\f = 12 - 10\\\\f = 2 \ N

Therefore, the greatest possible magnitude of the other force is 2 N.

Hence, this is the required solution.

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The use of liquid fuel revolutionized:
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Two spheres have identical charges and are 75 cm apart. the force between them is +0.30 n. what is the magnitude of the charge o
ella [17]

Answer:

4.33\cdot 10^{-6}C, charges are both positive or both negative

Explanation:

The electrostatic force between the two spheres is given by

F=k\frac{q_1 q_2}{r^2}

where

k is the Coulomb's constant

q1 and q2 are the charges on the two spheres

r is the distance between the centres of the two spheres

In this problem, we have

F=+0.30 N is the force

r=75 cm=0.75 m is the distance between the spheres

q_1 =q_2 =q because the two spheres have identical charge

Solving the formula for q, we find

q=\sqrt{\frac{Fr^2}{k}}=\sqrt{\frac{(+0.30 N)(0.75 m)^2}{9\cdot 10^9}}=4.33\cdot 10^{-6}C

And the two charges have the same sign (so, both positive or both negative), since the sign of the force is positive (+0.30 N), so it is a repulsive force.

5 0
3 years ago
Two circular holes, one larger than the other, are cut in the side of a large water tank whose top is open to the atmosphere. Ho
lidiya [134]

Answer:\frac{r_1}{r_2}=1.565

Explanation:

Given

two holes are made with different sizes

Hole 1 is large in size and hole 2 is small

If the volume flow rate of water is same for both the hole then small hole must be below the large hole because for same flow rate, velocity of water is large while cross-sectional area is small so it compensate to give same flow for both the holes.

Now for radius apply Bernoulli's theorem at hole 1 and 2

P_1+\rho gh_1=P_{atm}+\frac{1}{2}\rho v_1^2

P_2+\rho g6h_2=P_{atm}+\frac{1}{2}\rho v_2^2

if hole 1 is h distance below water surface then h_2=6h

and P_1=P_2=P_{atm}

Also v_1=\sqrt{2gh}

v_2=\sqrt{2g(6h)}

and Q=A_1v_1=A_2v_2

A=\pi r^2

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\dfrac{r_1}{r_2}=\sqrt{\dfrac{\sqrt{6h}}{\sqrt{h}}}

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I’m sorry I wish I knew the answer but I don’t I need this for points I’m so sorry
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