Answer:
Sunday, December 14, 2014
Instantaneous Velocity Sample Problem
1. A car is stopped at a traffic light. It then travels along a straight road so that its distance from the light is given by (a) x(t)=bt^2-ct^3, where b=2.40m/s^2 and c=0.120m/s^3. Calculate the average velocity of the car for the time interval to (b) Calculate the instantaneous velocity of the car at and (c) How long after starting from rest is the car again at rest?
Answer:
Answer:
Thursday, October 23, 2014
Organic Chemistry
What is Organic Chemistry?
Organic chemistry is the branch of chemistry that deals with organic molecules. An organic molecule is one which contains carbon, and these molecules can range in size from simple molecules to complex structures containing thousands of atoms! Although carbon is present in all organic compounds, other elements such as hydrogen (H), oxygen (O), nitrogen (N), sulphur (S) and phosphorus (P) are also common in these molecules.
Until the early nineteenth century, chemists had managed to make many simple compounds in the laboratory, but were still unable to produce the complex molecules that they found in living organisms. It was around this time that a Swedish chemist called Jons Jakob Berzelius suggested that compounds found only in living organisms (the organic compounds) should be grouped separately from those found in the non-living world (the inorganic compounds). He also suggested that the laws that governed how organic compounds formed, were different from those for inorganic compounds. From this, the idea developed that there was a ’vital force’ in organic compounds. In other words, scientists believed that organic compounds would not follow the normal physical and chemical laws that applied to other inorganic compounds because the very ’force of life’ made them different.
This idea of a mystical ’vital force’ in organic compounds was weakened when scientists began to manufacture organic compounds in the laboratory from non-living materials. One of the first to do this was Friedrich Wohler in 1828, who successfully prepared urea, an organic compound in the urine of animals which, until that point, had only been found in animals. A few years later a student of Wohler’s, Hermann Kolbe, made the organic compound acetic acid from inorganic compounds. By this stage it was acknowledged that organic compounds are governed by exactly the same laws that apply to inorganic compounds. The properties of organic compounds are not due to a ’vital force’ but to the unique properties of the carbon atom itself. Organic compounds are very important in daily life. They make up a big part of our own bodies, they are in the food we eat and in the clothes we wear. Organic compounds are also used to make products such as medicines, plastics, washing powders, dyes, along with a list of other items.
Organic chemistry is the branch of chemistry that deals with organic molecules. An organic molecule is one which contains carbon, and these molecules can range in size from simple molecules to complex structures containing thousands of atoms! Although carbon is present in all organic compounds, other elements such as hydrogen (H), oxygen (O), nitrogen (N), sulphur (S) and phosphorus (P) are also common in these molecules.
Until the early nineteenth century, chemists had managed to make many simple compounds in the laboratory, but were still unable to produce the complex molecules that they found in living organisms. It was around this time that a Swedish chemist called Jons Jakob Berzelius suggested that compounds found only in living organisms (the organic compounds) should be grouped separately from those found in the non-living world (the inorganic compounds). He also suggested that the laws that governed how organic compounds formed, were different from those for inorganic compounds. From this, the idea developed that there was a ’vital force’ in organic compounds. In other words, scientists believed that organic compounds would not follow the normal physical and chemical laws that applied to other inorganic compounds because the very ’force of life’ made them different.
This idea of a mystical ’vital force’ in organic compounds was weakened when scientists began to manufacture organic compounds in the laboratory from non-living materials. One of the first to do this was Friedrich Wohler in 1828, who successfully prepared urea, an organic compound in the urine of animals which, until that point, had only been found in animals. A few years later a student of Wohler’s, Hermann Kolbe, made the organic compound acetic acid from inorganic compounds. By this stage it was acknowledged that organic compounds are governed by exactly the same laws that apply to inorganic compounds. The properties of organic compounds are not due to a ’vital force’ but to the unique properties of the carbon atom itself. Organic compounds are very important in daily life. They make up a big part of our own bodies, they are in the food we eat and in the clothes we wear. Organic compounds are also used to make products such as medicines, plastics, washing powders, dyes, along with a list of other items.
Sunday, October 19, 2014
Density
An important property of any material is its density, defined as its mass per unit volume. A homogeneous material such as ice or iron has the same density throughout. We use (the Greek letter rho) for density. If a mass m of homogeneous material has volume V, the density is
Two objects made of the same material have the same density even though they may have different masses and different volumes. That’s because the ratio of mass to volume is the same for both objects.
The SI unit of density is the kilogram per cubic meter . The cgs unit, the gram per cubic centimeter is also widely used:
Densities of Some Common Substances
Fluids
A fluid is any material that can flow and that takes the shape of its container. Liquids and gases are fluids.For example, you could fill a fishbowl with water or with air.Each would take the shape of the bowl. Fluids can flow because the particles in fluids move past one another easily.
Fluid statics -the study of fluids at rest in equilibrium situations. Like other equilibrium situations, it is based on Newton’s first and third laws.
Fluid dynamics - the study of fluids in motion.
Fluid statics -the study of fluids at rest in equilibrium situations. Like other equilibrium situations, it is based on Newton’s first and third laws.
Fluid dynamics - the study of fluids in motion.
Stars
Composition of Stars
To learn what stars are made of, astronomers study the light from stars. When you look at white light through
a glass prism, you see a rainbow of colors called a spectrum (plural, spectra). The spectrum consists of millions of colors, including red, orange, yellow, green, blue, and violet. Astronomers use an instrument called a spectroscope to separate a star’s light into a spectrum. The spectrum gives astronomers information about the composition and temperature of a star.
Types of Spectra
A hot, solid object, such as the glowing wire inside a light bulb, gives off a continuous spectrum. A continuous spectrum shows all of the colors. However, hot gases emit only certain wavelengths of light, or colors. When a chemical element emits light, only some colors in the spectrum show up. All of the other colors are missing. The colors that appear are called emission lines. Every element has a unique set of bright emission lines that act like a fingerprint for that element.
Types of Stars
Thursday, October 16, 2014
10 Amazing Science Experiments you can do with Eggs
Watch these 10 amazing science experiments you can do with eggs. Very wow! And very simple to do.
Subscribe to:
Posts (Atom)