How is potential energy converted to kinetic energy and then heat?

How is potential energy converted to kinetic energy and then converted to heat?

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1. Depends on what you mean. Take a mass, lift it in the air so it has some potential energy, let it drop, it gains kinetic energy due to gravitational potential, it collides with a surface, transferring its kinetic energy in a semielastic collision with the molecules in the floor. The molecules are bound to their lattice structure and so the energy that strikes them plucks them like a guitar string and they oscillate back and forth in their given amount of space since they are bound. This is vibrational motion of bound particles is sort of a definition of heat. This can be given off by said molecules transferring the vibration to nearby air molecules thus raising their temperature.
2. "Potential energy" comes in many forms: Chemical energy - stored in the bonds of atoms and molecules. It is the energy that holds these particles together. Biomass, petroleum, natural gas, and propane are examples of stored chemical energy. Stored Mechanical Energy is energy stored in objects by the application of a force. Compressed springs and stretched rubber bands are examples of stored mechanical energy. Nuclear Energy is energy stored in the nucleus of an atom––the energy that holds the nucleus together. The energy can be released when the nuclei are combined or split apart. Nuclear power plants split the nuclei of uranium atoms in a process called fission. The sun combines the nuclei of hydrogen atoms in a process called fusion. Scientists are working on creating fusion energy on earth, so that someday there might be fusion power plants. Gravitational Energy is the energy of position or place. A rock resting at the top of a hill contains gravitational potential energy. Hydropower, such as water in a reservoir behind a dam, is an example of gravitational potential energy. ( http://www.eia.doe.gov/kids/energyfacts/science/formsofenergy.html ) SO let's look at gasoline. Base gasoline has a an energy content of approximately 116,090 btu/gallon. That gasoline, say a gallon of it, represents (chemical) potential energy that can be released. You hit the starter in your car, the engine fires up, and is producing MECHANICAL energy (kinetic) energy by the controled combustion of that gasoline to 'push' the pistons down in the cylinders. The product of that combustion is that the engine gets hot. VERY HOT. So hot that you need to circulate coolant around he cylinders and head to absorb that heat and dissapate it via the radiator. Simple, huh? As an addendum, ethanol has less potential chemical energy than gasoline: The energy of ethanol relative to gasoline A. 76,000 = BTU of energy in a gallon of ethanol B. 116,090 = BTU of energy in a gallon of gasoline C. .655 = 2/3 = GGE of energy in a gallon of ethanol. A / B. D. 1.53 = Gallons of ethanol with the energy of 1 gallon of gasoline. D = B / A. So you need a gallon and a half of ethanol to get the same energy that a gallon of gasoline yields. http://zfacts.com/p/436.html
3. Potential energy is rest energy and kinetic energy is energy of motion Total Energy = Kinetic + Potential Kinetic = 1/2 mv^2 Potential = 1/2 mgy so say you drop a ball from a certain height, before you drop it, it has 100% potential energy based on its position. as it falls it has both kinetic and potential energy since its height decreases but its velocity increases. When it hits the ground it has 100% kinetic energy since it has no height and is a max velocity. The total energy is always the same. Heat is just a measure of energy expelled from a object.
4. a body at a certain height above the ground has pot ener.if the object is dropped, it starts moving, and hence loses pot energy due to its decreasing height since pot enrgy = mgh, where m is mass, g is acceleration due to gravity =10ms-1 and h is the height above ground.so an object falling down has its height above ground decreasing, thus pot ener decreases. but according to principle of concervation of enegy, energy cannot b created nor destroyed but can b converted to other forms, so here since the object is moving it possess kine ener and here loss in pot ener while moving down=gain in kinetic ener since while being dropped object has a velocity and kine energy=0.5*mass*velocity^2. thus pot ener is converted to kine energ. then when body hits the ground, and stops to move the kinetic energy bcome 0, but again using principle of conservation of enegy, on hitting the ground, heat energy is formed by contact between object and ground, thus kine was converted to heat.