Friday, 30 November 2012

newton's law of motion

Newton's laws of motion

Redirected from Newton's second law of motion
The laws of motion (laws of inertia) are the three scientific laws which Isaac Newton described; regarding the motion of bodies. These laws are fundamental to classical mechanics.
Newton first defined these laws in Philosophiae Naturalis Principia Mathematica (1687) and, using his newly developed calculus, proved many results concerning "idealised" particles. In the third volume (of the text), he showed how, combined with his Law of Universal Gravitation, the laws of motion would explain Kepler's laws of planetary motion. Newton's laws were modified, in 1916, by Einstein's theory of relativity.
Newton's First Law (Law of Inertia)
  • Every object persists in its state of rest, or uniform motion (in a straight line); unless, it is compelled to change that state, by forces impressed on it.
  • A body remains at rest, or moves in a straight line (at a constant velocity), unless acted upon by a net outside force.
This means that a stationary object will remain stationary, and a moving object will continue to move (forever and in the same manner), unless a force acts upon it. In everyday life, the force of friction usually acts upon moving objects. Newton's law indicates that some force (gravity) must be acting upon the planets, as they do not travel in a straight line.
Newton's Second Law
This is expressed by the equation:
This expresses that the more force an object receives, the greater its acceleration will be; and that, the less mass an object has, the less force will be needed, to accelerate it; the more mass an object has, the more force will be required, to accelerate it. For example, the force of a nuclear explosion will acclerate a kitten more than a water buffalo; because, the kitten has less mass. This law is associated with the conservation of angular momentum.
Newton's Third Law
  • Whenever one body exerts force upon a second body, the second body exerts an equal and opposite force upon the first body.
  • For every action, there is an equal and opposite reaction.
  • Forces always come in equal pairs.
If you strike an object with a force of 200 N, then the object also strikes you (with a force of 200 N). Not only does a bullet exert force upon a target; but, the target exerts equal force upon the bullet. Not only do planets accelerate toward stars; but, stars acclerate toward planets. The reaction force has the same line of action, and is of the same type and magnitude as the original force.


Friday, 23 November 2012

effects of tsunami

Effects Tsunamis can Make 1. They can destroy lives/drowned loved ones.
2. Wash away properties.
3. Wash away and drowned pets.
4. The sound will make you scared and after it happens you might not be able to sleep well because you might hear the sound of a tsunami at night.
5. You won’t have anything to live like: Food, clothes, shelter, beds and blankets.


Friday, 16 November 2012

cause of tsunami

1. A Tsunami is violent disturbance deep below the ocean surface.
2. The under water earthquakes and subduction zones are the most common cause.
How a Tsunami Is Caused
When an oceanic plate hits a continental plate the plates press together and pressure builds.
Eventually the heavier oceanic plate slips under the lighter continental plate and causes an earthquake.
The earthquake lifts part of the ocean up and drops other parts down.
What happens on the ocean floor is mirrored on the surface of the water above.
The gravity acts fast to even out the water’s surface. The seismic energy created that big wave and it doesn’t just disappear. Waves start moving up to 600 miles per hour but you can’t see them.
The Tsunami extends thousands of feet deep into the ocean.
Tsunamis carry lots of water and energy so they can travel very far.


Saturday, 10 November 2012

what is tsunami?

  • Tsunamis are huge waves of water that are usually caused by earthquakes or volcanic eruptions.
  • As a tsunami approaches the shore, water may recede from the coast, if it is shallow enough the water may be pulled back hundred’s of metres. If you are in the area, observing this is a good indication that a tsunami is on the way.
  • Regions in tsunami danger zones often have warning systems in place to give people as much time to evacuate as possible.
  • When tsunamis hit shallow water (often near the coast) they slow down but increase in height.
  • An earthquake in the Indian Ocean off Indonesia in December 2004 caused a tsunami that killed over 200000 people in 14 countries.
  • In March 2011, the Tohoku earthquake off the eastern coast of Japan caused a tsunami that was a major factor in the death of over 15000 people.
  • The tsunami waves created by the Tohoku earthquake reached heights of over 40 metres (131 feet) in some areas, wiping out coastal towns and causing a number of nuclear accidents.
  • The Japanese word tsunami literally means ‘harbor wave’.
  • Tsunamis are sometimes referred to as tidal waves but this term has fallen out of favour because tsunamis are not related to tides.



Saturday, 3 November 2012

do you know who is thomas edison?

Legacy as an inventor

One of Edison’s mentors during those early years was a fellow telegrapher and inventor named Franklin Leonard Pope, who allowed the then broke youth to live and work in the basement of his Elizabeth, New Jersey home.
On December 25, 1871, he married Mary Stilwell, and they had three children, Marion Estelle Edison, Thomas Alva Edison, Jr., and William Leslie Edison. His wife Mary died in 1884. On February 24, 1886, he married 19 year old Mina Miller. They had an additional three children, Madeleine Edison, Charles Edison (who took over the company upon his father’s death) and Theodore Edison.
Edison, who made the famous quote, “genius is 99% perspiration; 1% inspiration” eventually invented the light bulb:

Thomas Edison died on Oct. 18th, 1931 in New Jersey at the age of 84 years.