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Gwar [14]
3 years ago
11

Name nine elements that have been around so long that we don't even know when they

Physics
2 answers:
sergeinik [125]3 years ago
8 0
What was the first known element? Actually, there were nine elements known to ancient man. They were gold, silver, copper, iron, lead, tin, mercury, sulfur, and carbon.
lora16 [44]3 years ago
7 0

Answer:

gold, silver, copper, iron, lead, tin, mercury, sulfur, and carbon

Explanation:

gold, silver, copper, iron, lead, tin, mercury, sulfur, and carbon

-  (These are the most longest elements that have been around very long )

You might be interested in
A quarterback passes a football from height h = 2.1 m above the field, with initial velocity v0 = 13.5 m/s at an angle θ = 32° a
SOVA2 [1]

Answer:

a)    x = v₀² sin 2θ / g

b)    t_total = 2 v₀ sin θ / g

c)    x = 16.7 m

Explanation:

This is a projectile launching exercise, let's use trigonometry to find the components of the initial velocity

        sin θ = v_{oy} / vo

        cos θ = v₀ₓ / vo

         v_{oy} = v_{o} sin θ

         v₀ₓ = v₀ cos θ

         v_{oy} = 13.5 sin 32 = 7.15 m / s

         v₀ₓ = 13.5 cos 32 = 11.45 m / s

a) In the x axis there is no acceleration so the velocity is constant

         v₀ₓ = x / t

          x = v₀ₓ t

the time the ball is in the air is twice the time to reach the maximum height, where the vertical speed is zero

          v_{y} = v_{oy} - gt

          0 = v₀ sin θ - gt

          t = v_{o} sin θ / g

         

we substitute

       x = v₀ cos θ (2 v_{o} sin θ / g)

       x = v₀² /g      2 cos θ sin θ

       x = v₀² sin 2θ / g

at the point where the receiver receives the ball is at the same height, so this coincides with the range of the projectile launch,

b) The acceleration to which the ball is subjected is equal in the rise and fall, therefore it takes the same time for both parties, let's find the rise time

at the highest point the vertical speed is zero

          v_{y} = v_{oy} - gt

          v_{y} = 0

           t = v_{oy} / g

           t = v₀ sin θ / g

as the time to get on and off is the same the total time or flight time is

           t_total = 2 t

           t_total = 2 v₀ sin θ / g

c) we calculate

          x = 13.5 2 sin (2 32) / 9.8

          x = 16.7 m

5 0
3 years ago
Volcanologists and seismologist are specialzed in what
antiseptic1488 [7]

The answer is:

They are specialized in geology and geophysics

1) Volcanologists are scientific researchers who study the properties of volcanoes and develop the science of predicting volcanic eruptions accurately.

- Volcanoes are the results of fissures in the earth's crust, from which magma, gases, rocks, and ashes can erupt.  


-Volcanic eruptions and their impact on the atmosphere are investigated by specialist geologists known as volcanologists.


A) Volcanologists are scientists who use a variety of sophisticated equipment to measure and analyze volcanic activity, lava, rock, ashes and gases as well as earthquakes caused by eruptions.


B) Also, they measure the magnitude and intensity of explosions, placing them on a scale from 1 to 8 [volcanic explosivity index].  


C)Volcanologists monitor both active and dormant volcanoes to try to predict eruptions and minimize adverse effects on people and their environment.


D)Also, they spend a lot of time collecting and analyzing samples of debris, rocks and other products from extinct volcanoes to gain a better understanding of the processes behind the volcanic activity and the impact former eruptions had in shaping the climate.


2) Seismologists are Earth scientists, specialized in geophysics, who study the genesis and the propagation of seismic waves in geological materials.


-Their research aims at interpreting the geological composition and structures of the Earth. In the case of earthquakes, seismologists evaluate the potential dangers and seek to minimize their impact through the improvement of construction standards.



5 0
3 years ago
Read 2 more answers
Choose all the answers that apply.
horrorfan [7]

Answer:

orbit the sun have very elliptical orbits

are made of frozen gas and ice

Explanation:

Comets are the made up of dry ice, frozen water, gases and dust particles. it is called dirty snow balls as their nucleus carry frozen water and pieces of rock.

Comets move around the sun in an elliptical orbits and follow Kepler's Laws saying that they move faster when closer to the Sun.

Comets have tails even when they are far from the sun and the tails that point away from the sun.

Hence, the correct options are "orbit the sun have very elliptical orbits and are made of frozen gas and ice".

6 0
3 years ago
Read 2 more answers
How is momentum conserved in a newtons cradle <br><br> when one steel ball hits the other
arsen [322]

In Newton's Cradle experiment we know that all cradles of same mass and identical to each other

Now we know that when two identical objects collide elastically then they interchange their velocity

So here we have same illustration

When Newton pulls up a cradle and release it will move hit another cradle which is at rest

Due to elastic collision between them first cradle comes to rest and another cradle will move ahead with same speed this process remains the same and one by one all cradle hit another.

So at the last the cradle at the end will move off with the same speed as the first cradle will hit with the speed.

So in this experiment the cradle at the last end will move off at same distance away from the right end as that of left end we pull the cradle.

So here we can say that in horizontal direction when all cradles are colliding each other there is no external force on the system so momentum is conserved and they all will move off with same speed and hence we observe the above condition.

8 0
3 years ago
A student analyzes data of the motion of a planet as it orbits a star that is in deep space. The orbit of the planet is consider
Valentin [98]

Explanation:

The orbit of the planet is considered to be stable and does not change over time. This means that the force of gravity and inertia are perfectly balanced. Leading to forward motion of Planet and moons under force of gravity of some other large body(Most probably stars).This is in turns leads to formation of orbit.

8 0
2 years ago
Read 2 more answers
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