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3 years ago

What are pollutants of greatest concern and who is at risk?

1 answer:

6 0

Oil leakage in aquatic areas. (fish)
Burning fuel. (Air/global warming)
Toxic waste burried in dirt (living Creatures)
Lights/Electricity (destroyes Birds migration)
Noise (migration on dolphines and other sea mammals)

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What do organisms need in order to reproduce? This is Science Btw

Delicious77 [7]

Answer:

Energy. They need energy.

Explanation:

7 0

2 years ago

Read 2 more answers

An astronaut lands on an alien planet. He places a pendulum (L = 0.200 m) on the surface and sets it in simple harmonic motion,

Ne4ueva [31]

A) f = 1.8 rev/s = 2 Hz
T = 1 / f = 0.55s

B) not really sure..srry

C) T = 2 pi √ ( L / g ) 
0.57 = 2 x 3.14 x √ ( 0.2 / g )

g = 25.5 m/s²

Hope this helps a little at least.. :)

5 0

2 years ago

The electron gun in a television tube accelerates electrons (mass = 9.11x10^-31 kg, charge = 1.6 x 10^-19C) from rest to 3 x10^7

stich3 [128]

Answer:

Electric field acting on the electron is 127500 N/C.

Explanation:

It is given that,

Mass of an electron, $m=9.11\times 10^{-31}\ kg$

Charge on electron, $q=1.6\times 10^{-19}\ C$

Initial speed of electron, u = 0

Final speed of electron, $v=3\times 10^7\ m/s$

Distance covered, s = 2 cm = 0.02 m

We need to find the electric field required. Firstly, we will find the acceleration of the electron from third equation of motion as :

$a=\dfrac{v^2-u^2}{2s}$

$a=\dfrac{(3\times 10^7)^2-0}{2\times 0.02}$

$a=2.25\times 10^{16}\ m/s^2$

According to Newton's law, force acting on the electron is given by :

F = ma

$F=9.1\times 10^{-31}\times 2.25\times 10^{16}$

$F=2.04\times 10^{-14}\ N$

Electric force is given by :

F = q E, E = electric field

$E=\dfrac{F}{q}$

$E=\dfrac{2.04\times 10^{-14}}{1.6\times 10^{-19}}$

E = 127500 N/C

So, the electric field is 127500 N/C. Hence, this is the required solution.

8 0

3 years ago

Hey guys, i need some help. I'm having a physics test tmmrow and I understand nothing :(. Can anyone plz explain or give me a br

professor190 [17]

We think of sound as something we hear—something that makes noise. But in pure physics terms, sound is just a vibration going through matter.

The way a vibration “goes through” matter is in the form of a sound wave. When you think of sound waves, you probably think of something like this:1

But that’s not how sound waves work. A wave like that is called a transverse wave, where each individual particle moves up and down to create a snake situation.

A sound wave is more like an earthworm situation:2

Like an earthworm, sound moves by compressing and decompressing. This is called a longitudinal wave. A slinky can do both kinds of waves:13

Sound starts with a vibration of some kind creating a longitudinal wave through matter. Check this out:4

That’s what sound looks like—except picture an expanding ripple of spheres doing that. In this animation, the sound wave is being generated by that vibrating grey bar on the left. The bar might be your vocal chords, a guitar string, or a waterfall continually pounding down into the river below. By looking at the red dots, you can see that even though the wave moves in one direction, each individual particle only moves back and forth, mimicking the vibration of the gray bar.

So instead of a curvy snake wave, sound is a pressure wave, which causes each piece of the air to be at either higher-than-normal pressure or lower-than-normal pressure. So when you see a snake-like illustration of a sound wave, it’s referring to the measure of pressure, not the literal path of movement of the particles:5

6 0

3 years ago

You use a slingshot to launch a potato horizontally from the edge of a cliff with speed v0. The acceleration due to gravity is g

sergij07 [2.7K]

Answer:

t = 2 v₀ / g

Explanation:

For this projectile launch exercise we use the displacement equations

x = vox t

y = y₀ + $v_{oy}$ t - ½ g t²

As it is launched horizontally the vertical velocity is zero and the point of origin of the coordinate system is here, so y₀ is zero.

x = v₀ t

y = ½ g t²

They ask us for the time for which

x = y

vo t = ½ g t²

t = 2 v₀ / g

8 0

2 years ago