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3 years ago

Is it true or false that air pollution only occurs as a result of human activity

Physics

2 answers:

gregori [183]3 years ago

8 0

Hi alexander it is very true air pollution is only caused by human activity

seraphim [82]3 years ago

8 0

Answer:

This is false

Explanation:

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Estimate the number of atoms in 1 cm^3 of a solid

dexar [7]

Avogadro's number: 6.02 x 10^23 atoms is present in 1mol of a solid (i.e. 22, 400 cm3)

Hence, in 1 cm3, 6.02 x 10^23 /22400 atoms is present = 2 x 10 ^ 19 atoms.

7 0

2 years ago

You are traveling 70 mph (31.3 m/s) and slam on the brakes to avoid hitting another car. How far do you travel if it takes you 8

Arlecino [84]

You traveled a distance of 620.075 meters if it takes you 8.5 seconds to stop.

Given the following data:

Initial velocity, U = 31.3 m/s

Time, t = 8.5 seconds.

We know that acceleration due to gravity (a) for an object is equal to 9.8 meter per seconds square.

To find the distance traveled, we would use the second equation of motion:

Mathematically, the second equation of motion is given by the formula;

$S = ut + \frac{1}{2} at^2$

Where:

S is the distance travelled.

u is the initial velocity.

a is the acceleration.

t is the time measured in seconds.

Substituting the parameters into the formula, we have;

$S = 31.3(8.5) + \frac{x}{y} (9.8)(8.5^2)\\\\S = 266.05 + 4.9(72.25)\\\\S = 266.05 + 354.025$

Distance, S = 620.075 meters.

Therefore, you traveled a distance of 620.075 meters if it takes you 8.5 seconds to stop.

Read more: brainly.com/question/8898885

6 0

2 years ago

an ice skater applies a horizontal force to a 20.-kilogram block on frictionless, level ice, causing the block to accelerate uni

stiv31 [10]

The only vertical forces are weight and normal force, and they balance since the surface is horizontal. The horizontal forces are the applied force (uppercase F) in the direction the block slides and the frictional force (lowercase f) in the opposite direction.

Apply Newton's 2nd Law in the horizontal direction:
ΣF = ma
F - f = ma
where f = µmg

F - µmg = ma
F = m(a +µg)
F = (20 kg)(1.4 m/s² + 0.28(9.8 m/s²)

F = 83 N

3 0

2 years ago

PLEASE ANSWER 50 POINTS SPENT I'LL GIVE BRAINLIEST TO THE PERSON WHO ANSWERS ALL! (or most)

Afina-wow [57]

Answer:

1) The matter absorbs or reflects the light

2) Lens

3) Concave- curves inwards. Diverges light

b.Convex- curves outward. Converges light

4) The image is real if the distance of the object from the lens is greater than the focal length and virtual if it is less than the focal length

5) Lens and, for convex lenses, on the distance between the lens and the object.

6) Index of refraction?

Explanation:

I hope this helped you, sorry if anything is wrong

6 0

3 years ago

An ideal heat engine absorbs 97.2 kJ of heat and exhausts 83.8 kJ of heat in each cycle. What is the efficiency of the engine?

r-ruslan [8.4K]

Answer:

13.7%

Explanation:

Given that,

Heat absorbed by the engine = 97.2 kJ

Heat exhausted by the engine in each cycle = 83.8 kJ

We need to find the efficiency of the engine. It is calculated by the formula.

$\eta=1-\dfrac{Q_e}{Q_a}\\\\=1-\dfrac{83.8}{97.2}\\\\=0.137\\\\=13.7\%$

so, the efficiency of heat engine is 13.7%.

5 0

2 years ago