How does the roller coaster work?

What you may not realize as you’re cruising down the track at 100 kilometre hour is that the coaster has no engine. The car is pulled to the top of the first hill at the beginning of the ride, but after that the coaster must complete the ride on its own. You are not being propelled around the track by a motor or pulled by a hitch. The conservation of potential energy to kinetic energy is what drives the roller coaster and all of the kinetic energy you need for the ride is present once the coaster descends the first hill. Once you are underway, different type of wheels help keep the ride smooth. Running wheels guide the coaster on the track. Friction wheels control lateral motion (movement to either side of the track). A final set of wheels keeps the coaster on the track even it is inverted. Compressed air brakes stop the car as the ride ends.

What is difference between mass and weight?

Mass is the amount of stuff in something. Weight is a measure of the amount of gravity acting on the stuff. If you were travel from earth to the moon, you would have the same mass but different weight. Why? Because the amount of stuff in you is always the same. The moon however has less gravitational force than the earth so you would weigh less. In fact, you’d only weigh 16 percent of what you weigh in earth.

Why coffee getting hotter after stir with milk?

Stirring a coffee involves a transfer of energy from you to the coffee. That’s because we are doing physical work on the coffee by pushing it around as it moves in the direction of your push. What began as chemical energy in your body becomes thermal energy in the coffee. That said, the amount of thermal energy you can transfer to the coffee with any reasonable amount of stirring is pretty small and you’d lose patience with the process long before you achieved any noticeable rise in the coffee temperature. The effect that you notice is more one of mixing than of heating. Until you mix the milk into the coffee, you may have hot and cold spots in your cup and you may notice that cold spots most strongly.

Why do turtles go so slowly?

Turtles are slow because they don’t have to go fast! Most turtles are herbivores, which mean they eat plants. Plants don’t run, so they are fairly easy to eat. Also, they have thick shells to protect them from prediators. If you have ever picked up a turtle, you have seen how they can tuck in their heads and feet. Physically, they are slow because they have pretty slow metabolisms which mean their bodies process energy slowly. But animals with slow metabolisms often have longer lives. Some turtles live for more than one hundred years! Slow and steady also wins the race.

Do eyelashes grow back like your hair does?

Eyelashes do grow back-it usually takes two to three months to grow a new one. Your eyelashes protect your eyes from dust and light, and are important part of your integumentary systems, which included your hair, nails and skin. Did you know that as a human we have over 100,000 hairs on your head? Also this may sound gross, but there are tiny insects that live in your eyelashes called demodicids that are eat dead skin. They are perfectly natural and helps keep your eyelashes clean.

Why do people get goosebumps?

Our body is hairy and goosebumps have a lot to do with hair, muscles and skin. All over your body, you have tons of small hair. And underneath the skin, there are tiny muscles attached to the ase of these hairs. You get goosebumps when these tiny muscles pull the hairs until they are standing straight up at attention and your skin bunches together into little bumps. Generally, you get goosebumps when you are colds but sometimes you can get them when you are frightened or something gives you ‘the chills’

What happens when you have an asthma attack?

If you have asthma, however, taking in air can be perilous challenge. In fact, it can make you feel like you are drowning. Asthma is a lung disease that involves having overly sensitive tissues in your airways. These tissues are always inflamed, even if you don’t feel irritated. Dust, pollen, mould spores, and even cold air can trigger reactions in these tissues, making the bronchial tubes swell, excrete thick mucus and plug smaller air passageways. This can make your chest feel tight and cause coughing, wheezing and breathlessness for several hours unless you use special medication. Researchers says that people in crowded cities are particularly at risk for asthma attacks because they are exposed to more icky allergens like dust mites, air pollution and cockroach droppings. While people don’t really outgrow asthma, about half of all kids who have it will experience few, if any, symptoms by the time they become teens. That is because small amounts of narrowing have less impact on airways as they grow larger.

Why are adults stinkier than kids?

Humans are a collection of wondrous and different odours! When humans reach their long-awaited adolescence, they begin to stink in entirely new and even stinkier ways! All over your skin – the soles of your feet, the palms of your hands, your forehead – you have small pores that ooze sweat from glands underneath the skin. Why? Because sweat is the wonderful natural air conditioning that keeps animals like you humans cool. So, what happens to the sweat? Some gets evaporated quickly, and some sits around long enough for bacteria to begin to gather. These microscopic living things just love to munch on dead skin cells and some of the ingredients in sweat. Sometimes, mould, fungus and other microbes decide to join them and cause stinky shoes, stinky feet and stinky humans. Now when humans reach adolescence, they begin a second kind of sweat.

What makes hair curly or straight?

You inherit from your parents genes which help determine whether your hair will be straight, curly, wavy, frizzy, thick or thin. But what actually makes your hair wave, or frizz or lie there bone straight is the shape of the hair itself. If you were able to cut a hair in half and look at it sideways you would notice that curly hair is shaped like rectangle, wavy hair like oval and straight hair like a circle. And that shapes determines whether your hair hangs down straight or spirals in the circle or waves in a curve.

what is biomass?do you know what is it?..

Biomass is any organic materials made from plants or animals. Domestic biomass resources include agricultural and forestry residues, municipal solid waste and industrial waste. It can be converted to other usable forms of energy and is an attractive petroleum alternative for a n umber of reasons. First, it is renewable resources that is more evenly distributed over the earth’s surface than are finite energy sources and may be exploited using more environmentally friendly technologies. Agriculture and forestry residues, and in particular residues from paper mills, are the most common biomass resources used for generating electricity and power, including industrial process heat and steam, as well as for a variety of bio based products. Use of liquid transportation fuels such as ethanol and biodiesel, however, currently derived primarily from agricultural crops, is increasing dramatically.

estidotmy

30 julai 2008

what is biopower??..

Biopower is the use of biomass to generate electricity, or heat and steam required for the operation of a refinery. Biopower system technologies include direct-firing, cofiring, gasification, pyrolysis, and anaerobic digestion. Most power plants use direct-fired systems. They burn biomass feedstock directly to produce steam. This steam drives a turbine, which turns a generator that converts the power into electricity. In some biomass industries, the spent steam from the power plant is also used for manufacturing processes or to heat buildings. Such combined heat and power systems greatly increase overall energy efficiency. Paper mills, the largest current producers of biomass power, generate electricity or process heat as part of the process for recovering pulping chemicals.

estidotmy

30 july 2008

VINT CERF - FATHER OF THE INTERNET

“The net will stop being a part of the telephone network. Instead the telephone network will become a part of the net.”- Cerf

Vinton Gray Cerf (born June 23, 1943 in New Haven, Connecticut). As a graduate student at UCLA, he was involved in the early design of the ARPANET. He was present when the first IMP was delivered to UCLA. He is called the father of the internet. He earned this nickname as one of the co-authors of TCP/IP-the protocol that allowed ARPA to connect various independent networks together to form one large network of networks-the internet. He headed a group in 1973 with Bob Kahn that invented the TCP/IP protocol. He joined the board of the internet corporation for Assigned Names and Numbers or ICANN in 1999 and is currently serving a term until 2007. In 2001, he was awarded the Strowger Award from Ohio University’s J.W. McClure School of communication systems management. In October 2002,he was awarded (together with Bob Kahn, Larry Roberts and Tim Berners-Lee) Premio Principle de Asturias de Investigacion Cientifica, the most distinguished Spanish award. In early 2005 it was announced that Cerf, along with Robert Kahn were named the ACM’s 2004 Turing Award winners for their work on the design of internet protocols.