Notes, abstracts, papers, exams and problems of Physics

Earth, Moon, and Space: Key Concepts

1. Day and night are caused by:

   d. Earth's rotation on its axis.

2. Earth's rotation takes about:

   c. 24 hours.

3. One complete revolution of Earth around the sun takes about:

   c. one year.

4. Earth has seasons because:

   c. Earth's axis is tilted as it moves around the sun.

5. When the north end of Earth's axis is tilted toward the sun, North America will experience:

   d. more direct rays and longer days.

6. In the Southern Hemisphere, the summer solstice occurs when the sun is directly overhead at:

   b. 23.5° south latitude.

7. An equinox occurs when:

   a. neither end of Earth's axis is tilted toward nor away from the sun.

8. Because the moon rotates once for each revolution around Earth,

   c. you never see the far side of the moon.

9. The phase of the moon

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" »

Introduction

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.

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,

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 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

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