Potential vs. Kinetic Energy Which 2 points represent kinetic energy?
Kinetic and Potential Energy. Kinetic Energy Kinetic energy is the energy of movement or motion To...
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Transcript of Kinetic and Potential Energy. Kinetic Energy Kinetic energy is the energy of movement or motion To...
Kinetic and Potential Energy
Kinetic Energy
• Kinetic energy is the energy of movement or motion
• To calculate kinetic energy you need to know an object’s mass and velocity
• Kinetic energy (KE) = ½ (m)*(v2) = ½ mv2
• Energy is expressed in Joules (J) which are kg*m2/s2
Example how to calculate kinetic energy
A 0.10 kg bird is flying at a constant speed of 8.0m/s. What is the bird’s kinetic energy?
Mass (m) = .10kgSpeed (v) = 8.0m/s2
KE = ½ (.10kg)* (8.0m/s)2
KE = 3.2 kg*m2/s2 = 3J
Kinetic Energy Equations
• If you are asked to solve for kinetic energy use• KE = ½ mv2
• If you are asked to solve for mass use• M = 2*(KE)/v2
• If you are asked to solve for velocity use• V = square root 2KE/m
Potential Energy
• Potential energy is the energy stored as a result of position
• Gravitational potential energy depends on an object’s height
Formula for calculating potential energy
• The formula is PEg = mgh = Fgh
• Fg will be in Newtons
• Where m = mass, g = gravity and h = height• In the second form • F = force in newtons(N), h = height• Gravitational potential energy is expressed in
Joules (J)
Example of calculating gravitational potential energy
• A diver at the top of a 10.0 m high diving platform has a mass of 50.0kg. What is her potential energy?
• PE = mgh• PE = (50.0kg)*(9.8m/s2)*(10.0m)• PE = 4900 kg*m2/s2 = 4900J
Potential Energy Equations
• If you are asked to solve for potential energy use• PE = mgh or PE = Fgh
• If you are asked to solve for mass use• m = PE/gh or m = PE/Fgh
• If you are asked to solve for height use• h = PE/mg or use h = PE/Fg
Elastic Potential Energy
• Elastic potential energy is the energy stored in an object that is stretched or compressed (think elastic)
• The energy is stored when the object is either stretched or compressed
Chemical Energy
• Chemical energy is the energy stored in chemical bonds
• The energy is released when the bonds are broken
Electric Energy
• Electric energy is the energy associated with electric charges
• Batteries contain electric energy
Nuclear Energy
• Nuclear energy is the energy stored in the nucleus of an atom
• Energy can be released by nuclear fission which is splitting the atom or by nuclear fusion which is joining nuclei