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Clockwise and Counterclockwise Directions, Newton, Perpendicular, Pivot, Elastic, and Spring

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Clockwise

in the same direction as the movement of the hands on a clock

Counterclockwise

in the opposite direction to the movement of the hands on a clock

Newton

the unit of measurement for force

Perpendicular

at a 90-degree angle to something

Pivot

a fixed point that something balances or turns on

Elastic

a material or object able to resume its original shape after stretching or compressing

Elastic Limit

the extent to which an object can be stretched without permanently altering its size or shape

Extension

the increase in the length of something

Spring

a constant measure of how stiff or strong a spring is

Formulas:

s = d/t
d = s * t
t = d / s

Reading Practice Answers

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Course 2013:

Are Mobile Phones Dangerous?

  1. It is not clear at all. Some studies support this theory, while others completely contradict it. Therefore, the article is not entirely clear on the matter.
  2. No, they are not the only dangerous devices. Other wireless devices such as laptops, cordless phones, or gaming consoles can also be dangerous for our health.
  3. Because mobile phones emit Electromagnetic Radiation, which can be dangerous for children whose brains are not yet fully developed.
  4. FALSE. (lines 4-5): "Mobile phone...in radio frequency"
  5. TRUE. (lines 13-14): "Many years ago,...on their health"
  • 6. Concern
  • 7. Healthy
  • 8. Scare
  • 9. Device
  • 10. What do some health professionals point out?
  • 11. In spite of being very expensive, she bought the car.
  • 12. Smoking
  • 13.
... Continue reading "Reading Practice Answers" »

Discovering Extrasolar Planets: Methods and Significance

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Extrasolar Planets

An extrasolar planet is a planet orbiting a star other than our Sun. There are two general ways of learning about a distant object: directly, which means by obtaining images or spectra of the object, and indirectly, which means by inferring the object’s existence or properties without actually seeing it. There are two major indirect approaches to finding and studying extrasolar planets:

  1. Observing the motion of a star to detect the subtle gravitational tugs
  2. Observing changes to a star’s brightness that occur when one of its planets passes in front of the star as viewed from Earth.

Planets exert gravitational tugs on their star, causing the star to orbit around the system center of mass. Gravitational tugs: we can detect a... Continue reading "Discovering Extrasolar Planets: Methods and Significance" »

I choose to live

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Introduction


"The Breedlove´s did not live in a storefront because they were having temporary difficulties adjusting to the cutbacks at the plant. They lived there because they were poor and black, and they stayed there because they believed they were ugly" (The Bluest Eye, Toni Morrison, page 38).

Toni Morrison has portrayed in a very special way an specific social group all allong the novel (as you saw on the quote), this specific group is very related to Morrison, That´s why many other writers admire Morrison, by her hability to describe the background on her novels.

The social group/class described in the novel is the african american middle-low class which is represented by the main character family.
Morrison is able to write about this
... Continue reading "I choose to live" »

During a climb, if the total pressure head is rapidly clogged up by ice, the sensed total pressure remains constant and:

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Write your text here!Bernoulli's theorem, in fluid dynamics, relation among the pressure, velocity, and elevation in a moving fluid (liquid or gas), the compressibility and viscosity (internal friction) of which are negligible and the flow of which is steady, or laminar.


he principle of work and kinetic energy (also known as the work-energy theorem) states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle.

The law of conservation of momentum states that for two objects colliding in an isolated system, the total momentum before and after the collision is equal. This is because the momentum lost by one object is equal to the momentum gained by the other.

 the law
... Continue reading "During a climb, if the total pressure head is rapidly clogged up by ice, the sensed total pressure remains constant and:" »

Quantum Phenomena Explained

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Photons and Electrons in the Double Slit Experiment

Evidence for Wave-Particle Duality

  • A single electron or photon leaves the source with particle-like discreteness and creates a single discrete spot on the screen.
  • The interference pattern, which occurs over time, is a wave property.

Diffraction Pattern and Heisenberg’s Uncertainty Principle

  • We cannot measure the exact position of each electron or its exact momentum as it approaches the slit; there is uncertainty in both position and momentum.
  • The uncertainty in each electron’s y-position is reduced to the width of the slit (since we are certain it passes through the slit). This increases its uncertainty in the momentum of the y-direction.
  • The uncertainty in the momentum in the y-direction means
... Continue reading "Quantum Phenomena Explained" »

Understanding Electrostatics: Charge, Fields, and Lightning

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Understanding Electrostatics

Electrostatics is the branch of physics that studies the phenomena produced by charges that do not vary or move.

History of Electrostatics

6th century BC: The Greeks discovered the electrical properties of amber. When rubbed, it could attract light objects.

18th century: Benjamin Franklin conducted experiments with different materials and observed that rubbed materials could either attract or repel each other.

Franklin's Theory of Electricity

  • There are only two types of electricity: positive and negative.
  • Electricity is a sort of fluid present in all objects and it can flow from one object to another by rubbing them.
  • When there's an excess of electricity, objects have positive electricity, and when there's a lack of electricity,
... Continue reading "Understanding Electrostatics: Charge, Fields, and Lightning" »

Evolution of Soccer Balls: From Superball to Jabulani

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Good morning today we are going to present the evolution of soccer balls.


Superball

The superball was a soccer ball that consisted of a chamber composed of a valve that prevented the air from coming out and a seam from outside to inside that was invisible and without a flange. This ball was the first ball made without tiento


Invention of the Invisible Tiento

In Bell Ville, in the Argentine province of Córdoba between 1929 and 1931 Romano Polo, Antonio Tossolini and Juan Valbonessi conducted numerous tests and trials that culminated in the invention of the ball with an invisible tiento, a ball that continued to be used for a couple of years.


Professional Use and Commemoration

The superball was first used professionally in the same year of its invention... Continue reading "Evolution of Soccer Balls: From Superball to Jabulani" »

Zaha Hadid and the BMW Central Building: Accomplishment vs. Activity

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Zaha Hadid was designing the BMW Central Building.

The eventuality described in the VP ‘design the BMW Central Building” is [-static, +durative, +telic], thus an accomplishment. As shown in this example, it is compatible with the progressive, which emphasizes the progress of a [+durative] eventuality. Three diagnostics can be used to show that this event is an accomplishment, not an activity:

  1. It is compatible with in-PPs ('Zaha Hadid designed the BMW Central Building in three months.'), but not with for-PPs ('Zaha Hadid designed the BMW Central Building in three months').
  2. It does not have the sub-interval property: A subinterval of the event described in ‘Zaha Hadid designed the BMW Central Building’ cannot be described as ‘Zaha Hadid
... Continue reading "Zaha Hadid and the BMW Central Building: Accomplishment vs. Activity" »

El Método Científico y las Unidades Fundamentales

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The Scientific Method

1. How to Ask a Question?

2. Formulate a Hypothesis

3. Investigation Design (Experimentation)

4. Observe, Measure, and Collect Data

5. Analyze and Perform Results using data tables

6. Contrast Your Hypothesis

7. Share Results and Draw a Conclusion

Fundamental Units

Length: meter (m) Mass: kilogram (kg)

Time: second (s) Temperature: kelvin (K)

Derived Units

Area: square meter (m2) Volume: cubic meter (m3)

Speed: meters per second (m/s)

Acceleration: meters per second square (m/s2)

1 atm: 760 mmHg, 1013 mb, 101325 Pa