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What is static friction?

Static friction is what keeps an object stationary when it is placed on a surface. It is, for example, what keeps a wooden block from sliding down a small incline. Static friction varies based on the force applied to the object, but has a maximum value. This is calculated by multiplying the coefficient of static friction by the normal force (the force applied perpendicular to the object).The coefficient of static friction itself varies depending on the pair of materials in contact and is measured based on the angle of inclination at which motion just starts to occur. In general, rough objects ..

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How far is Jupiter from Saturn?

Since the planets don't orbit each other in a perfect circle, the distance between each of them varies greatly during their orbits. Jupiter has a distance of 484 million miles from the sun, making it the fifth planet from the ball of fire. Saturn is the sixth planet from the sun with a distance of 866 million miles. Both of these planets are considered gas giants and do not have a solid surface like Earth.

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What countries have the longest daylight hours?

Both the Arctic and the Antarctic have the most daylight hours. The countries in the region have weeks of continuous daylight. Every year these countries have days where the sun never goes down. In other parts of the region the sun sets, but for a short amount of time. Because of these long hours of light, this area is called "The Land of the Midnight Sun."The Arctic region north of the Arctic Circle has the greatest number of daylight hours during the Northern Hemisphere's summer.The Antarctic includes almost all of Antarctica south of the Antarctic Circle, and has the greatest number of..

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What instruments are used to study plate tectonics?

Scientists first started using GPS satellites to measure plate tectonics in the 1980s. A magnitude-7.1 earthquake that hit San Francisco allowed scientists to measure the movements of GPS markers that were already in place along the San Andrea fault. This GPS data allowed scientists to determine the direction and pattern of the fault's movement.\nThe precision of GPS satellites gives scientists the means to measure multiple types of plate movements. Researchers install GPS receivers at certain monitoring points and collect data once every year or so, which allows them to measure the slow ..

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What is a wire ampacity table?

A wire carrying a current beyond its amp limitations can overheat and become hazardous. For example, 14-gauge copper wire can carry an amperage load of up to 15 amps, while 12-gauge copper wire can carry a 20-amp load. Aluminum wire in a 12-gauge size is limited to a 15-amp load. Proper wire size is determined by American Wire Gauge standards and enforced by the National Electrical Code.

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What does an anemometer measure?

Anemometers are also used in mines, aviation navigation and ventilation systems. Variations of the anemometer include a three-cup and a propeller-driven design. The more quickly the wind is blowing, the faster the cups or propeller spins, providing an accurate wind speed in miles per hour, kilometers per hour or knots. In order to provide a wind direction, an anemometer must have a weather vane, and it always points in the direction from where the wind originates.

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What is the mass-mass percent concentration of a solution?

For example, if given a solution that contains 5.0 grams of a solute and 110.0 grams of solvent, then the mass-mass percent concentration of the solute is 5.0 grams/(5.0 +110.0) x 100 percent, which is equal to 4.35 percent.The mass-mass percent composition formula is only one of many methods used to express the mass percentages of solutes and solvents that make up a solution. Some others are molarity mole fraction and molality. However, these other formulas involve using other known quantities like moles and volume.

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Is PF5 polar or nonpolar?

PF5 has a trigonal bipyramidal configuration, consisting of a central phosphorus atom surrounded by five fluorine atoms. To visualize this structure, start with a trigonal planar configuration of three fluorine atoms bonded to the phosphorus. Above and below the plane (at the "top" and "bottom" of the molecule) are two more fluorines. The electronegativities of the three planar fluorines cancel each other out, as do the electronegativities of the fluorines above and below the plane. Therefore there is no net polarity, and PF5 is a nonpolar molecule.

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How does respiration work?

Respiration is a chemical process that involves the release of energy from glucose and other food substances. Higher animals typically have advanced physiologic respiratory systems for transporting oxygen-rich air to different body tissues. Terrestrial higher animals obtain air through the nose or mouth and carry the oxygen to a respiratory structure, such as the trachea. The alveoli in the lungs take in oxygen and expel waste carbon dioxide. The oxygen goes into the bloodstream through the hemoglobin.\nAll animals use biochemical respiration to deliver oxygen across the cell wall, and they us..

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Is nitrogen diatomic?

Nitrogen in its diatomic form exists in the atmosphere and comprises 78 percent of it. Nitrogen is normally an inert nonmetal, meaning it doesn't readily react, but some organisms utilize nitrogen in such a way to create amino acids and proteins. These amino acids and proteins are then used by nearly all forms of life on Earth. The human body is 3 percent nitrogen.

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