In which situation does the reactive force between two colliding objects cause a physical change? (1 point)

What do zooplankton and krill have in common?

serious [3.7K]

<h2><em>Hello, thank you for choosing brainly today. My name is Ethan and I'll be solving your question. </em><em><u>"What do zooplankton and krill have in common?"</u></em></h2>

Krill and plankton are two groups of organisms found in the ocean. Krill are species of crustacean related to shrimp, and serve as a very important link in the food chain of the sea. Plankton consist of a larger group of organisms with much more variety, including bacteria, algae, protozoans, jellyfish and some species of cephalopods.

Propulsion

The primary factor that determines whether a species is plankton or not is propulsion. Plankton organisms lack the ability to swim against the tide, and instead float from place to place on sea currents. They may be capable of some movement, and some types of plankton can even hunt for food, but none is powerful enough to make its own headway through the ocean. Adult krill are capable of swimming against currents, but their larvae and eggs fall into the plankton category.

Variation

Krill are crustaceans of the Euphausiacea order, which consists of 86 different species. Plankton, on the other hand, can come from a wide variety of different species and orders. Plankton fall into three broad categories, depending on their primary function. Phytoplankton are plant-like organisms, capable of photosynthesis. Zooplankton are animal plankton species that get their nutrients by eating other microscopic organisms. Bacterioplankton are the smallest plankton, and often serve as food for zooplankton and other lifeforms.

Appearance

Krill species have similar characteristics and generally resemble tiny shrimp. Most species reach around 2 centimeters (0.8 inches) as adults, while the largest species can reach sizes of up to 15 centimeters (5.9 inches). Plankton, on the other hand, consists of organisms of many different shapes and sizes. The smallest categories include microscopic viruses, protozoans, small crustaceans, and other tiny organisms. At the larger end of the scale, megaplankton are any plankton over 2 centimeters (0.8 inches) in size, and include large animals, such as cephalopods and jellyfish. The largest plankton is the lion's mane jellyfish, which can reach 2.5 meters (8.2 feet) in diameter and grow tentacles more than 36.5 meters (120 feet) long.

Role

Plankton and krill serve similar, but slightly different, roles in the food chain. Phytoplankton synthesize nutrients, while bacterioplankton recycle nutrients from decomposing matter in the ocean, providing some of the fundamental sources of nutrition for all ocean creatures. Zooplankton serve to concentrate those nutrients by eating smaller plankton and serving as food for larger creatures. Krill are one step up in the food chain, eating plankton and serving as a nutrient bridge from microscopic life forms to larger fish and mammals.

6 0

3 years ago

Using 0.500 g of nichrome, you are asked to fabricate a wire with uniform cross-section. The resistance of the wire is 0.673 Ω.

mojhsa [17]

Explanation:

Given that,

Mass of Nichrome, m = 0.5 g

The resistance of the wire, R = 0.673 ohms

Resistivity of the nichrome wire, $\rho=10^{-6}\ \Omega -m$

Density, $d=8.31\times 10^3\ kg/m^3$

(A) The length of the wire is given by using the definition of resistance as :

Volume,

$V=A\times l\\\\A=\dfrac{V}{l}\\\\Since, V=\dfrac{m}{d}\\\\V=\dfrac{m}{d}\\\\V=\dfrac{0.5\times 10^{-3}}{8.31\times 10^3}\\\\V=6.01\times 10^{-8}\ m^3$

Area,

$A=\dfrac{V}{l}\\\\A=\dfrac{6.01\times 10^{-8}}{l}$ ....(1)

$R=\rho \dfrac{l}{A}\\\\l=\dfrac{RA}{\rho}\\\\l=\dfrac{0.673\times 6.01\times 10^{-8}}{l\times 10^{-6}}\\\\l=0.201\ m$

(b) Equation (1) becomes :

$A=\dfrac{6.01\times 10^{-8}}{l}\\\\A=\dfrac{6.01\times 10^{-8}}{0.201}\\\\\pi r^2=3\times 10^{-7}\\\\r=\sqrt{\dfrac{3\times 10^{-7}}{\pi}} \\\\r=3.09\times 10^{-4}\ m$

Hence, this is the required solution.

5 0

3 years ago

While entering a freeway, a car accelerates from rest at a rate of 2.40 m/s2 for 12.0 s. (a) Draw a sketch of the situation. (b)

ArbitrLikvidat [17]

Answer:

a) See attached picture, b) We know the initial velocity = 0, initial position=0, time=12.0s, acceleration= $2.40m/s^{2}$ , c) the car travels 172.8m in those 12 seconds, d) The car's final velocity is 28.8m/s

Explanation:

a) In order to draw a sketch of the situation, I must include the data I know, the data I would like to know and a drawing of the car including the direction of the movement and its acceleration, just like in the attached picture.

b) From the information given by the problem I know:

initial velocity =0

acceleration = $2.40m/s^{2}$

time = 12.0 s

initial position = 0

c)

unknown:

displacement.

in order to choose the appropriate equation, I must take the knowns and the unknown and look for a formula I can use to solve for the unknown. I know the initial velocity, initial position, time, acceleration and I want to find out the displacement. The formula that contains all this data is the following:

$x=x_{0}+V_{x0}t+\frac{1}{2}a_{x}t^{2}$

Once I got the equation I need to find the displacement, I can plug the known values in, like this:

$x=0+0(12s)+\frac{1}{2}(2.40\frac{m}{s^{2}} )(12s)^{2}$

after cancelling the pertinent units, I get that my answer will be given in meters. So I get:

$x=\frac{1}{2} (2.40\frac{m}{s^{2}} )(12s)^{2}$

which solves to:

$x=172.8m$

So the displacement of the car in 12 seconds is 172.8m, which makes sense taking into account that it will be accelerating for 12 seconds and each second its velocity will increase by 2.4m/s.

d) So, like the previous part of the problem, I know the initial position of the car, the time it travels, the initial velocity and its acceleration. Now I also know what its final position is, so we have more than enough information to find this answer out.

I need to find the final velocity, so I need to use an equation that will use some or all of the known data and the unknown. In order to solve this problem, I can use the following equation:

$a=\frac{V_{f}-V_{0} }{t}$