Light rays bend when they enter from one medium to another of different density. The amount of bending is determined by the refractive indices of the two media. If one medium has a particular curved shape, it functions as a lens. The cornea, humours, and crystalline lens of the eye together form a lens that focuses images on the retina. Our eyes are adapted for viewing in air. Water, however, has approximately the same refractive index as the cornea (both about 1.33), effectively eliminating the cornea's focusing properties. When our eyes are in water, instead of their focusing images on the retina, they now focus them far behind the retina, resulting in an extremely blurred image from hypermetropia.

Friction is any force that opposes another force, like the force of gravity on a rocket or the tread of a shoe on a court. Without friction a swimmer would not move through the water when they pull/kick. Friction also keeps their togs on :D

Temperature does not affect the bounce of a rubber ball. Let's say you bounce a rubber ball on the grass. The result will be different then bouncing a rubber ball on a concrete surface. The result is different because you are using a solid, hard surface to bounce the ball with. But the temperature will not affect the bounce of a rubber ball. you can test it out for youself.

Pretty much everything in this universe involves velocity since velocity is practically the speed of an object when a tennis ball is hit it has both a horizontal and vertical velocity also the movement of a tennis racket has a great velocity, also the movement of the players across the court have a very inconsistent velocity especially in single's matches.

The youth of today may become the agents of national security in the future. They will train to work in all capacities of national security.

Yes, it uses data collection and analysis to determine players' current forms, geometry to determine which formation is best suited for each situation, objectives and opposition, physics in making a ball swerve its trajectory when struck, biology in player preparation and recovery, etc.

Walking Drawing coloring in pictures ? having sex ? giving anal ? having a tug ? having a finger ?

kabaddi players rub their hands with soil so as to provide a better grip of their opponent

-Neeldri Roy

== to lose weight or to get fit You either use it or lose it. If you stop using a muscle, it will deterioate. In the elderly, If you cease activity, the body starts to shut down those parts and they will not function. The heart is a muscle too and it too needs activity to keep healthy.

You can fix a balloon type pool with a patch. Most of these pools come with a patch. If not, you can purchase one at a pool outlet. All you have to do is put some glue on one side of the patch and attach it to the pool. Press hard and allow the patch to dry.

Fish breathe using gills. Gas exchange occurs in a structure of the gills called the gill fillaments. Blood in the fillaments flows in the opposite direction of water, this is called a counter current system. Some fish will swim against water currents to increase the amount of oxygen they are getting. There are also some fish that, in addition to the gills, can gulp air and the oxygen diffuses in the fishes swim bladder.

a water fall

The various species of fish found in oceans, lakes, rivers and streams have evolved over millions of years and have adapted to their preferred environments over long periods of time. Fish are categorized according to their salinity tolerance. Fish that can tolerate only very narrow ranges of salinity (such freshwater fish as goldfish and such saltwater fish as tuna) are known as stenohaline species. These fish die in waters having a salinity that differs from that in their natural environments.

The only fish I know of that lives in both is Pacific salmon. Salmon are born and they reproduce in the safety of freshwater but spend the rest of their lives in the oceans. This type of fish (fresh and salt water) are called anadromous.

65% of the world is landfill.

Pretty sure that is incorrect. I'd really like to know where the previous answerer pulled that figure from.

This is the best estimation I can find, from Yahoo Answers:

"The average person generates about a ton of trash every year. That translates to about 100 cubic feet a year in landfill (including dirt). We've had an average of 5 billion people in the world for the past 50 years since post WW2. That comes to 25 trillion cubic feet of landfill. Average depth of a landfill is 100 feet, so there are probably around 250 billion square feet of landfill. A square mile is 25 million square feet. So, that means about 10,000 square miles is landfill. Now, the Earth has 200 million square miles of surface, of which 50 million is dry land. Thus, 1/5000 of dry land area is taken up by landfills, or 0.02% It's actually quite tiny, as compared to land used for grazing or agricutlure, which is close to 10% to 20%."

Both liquid and gas

Aluminum foil can take upwards of four hundred years to decompose without any assistance. That time can be reduced by exposure to certain acids or chemicals.

A wakeboard is made by a wakeboard manufacturer, like Liquid Force, Hyperlite, CWB, Ronix, and others

Momentum is mass times velocity, and it is a vector, so it has a direction.

This boulder has a momentum of 100*5=500 kgm/s in the direction of its motion.

the garbage slowly goes into the water....pollution

which leads to not making it safe for animals

# Toilet paper is made from either recycled paper or wood chips. # It is mixed with water and broken down into a slurry, like paper mache.

# Any paper clips and staples are removed with magnets and filters.

# The ink is removed.

# The great soggy mass is then pressed through rollers which dry it.

# It then goes through a machine that perforates it every 10 cm and puts it onto a long roll.

# This long roll is then chopped up into lengths and wrapped and packaged.

The position of an athlete can affect their performance, there will be a good effect when the position of the athlete is exact and correct because in this way they can perform a right thing and produce a productive, useful, interesting and wonderful performance.

Yes, b/c a life jacket in an inflatable sleeveless jacket which is worn to keep a person afloat when they're in danger of drowning. Therefore, the answer is yes, b/c it will make you float on the surface... no matter what you do