1. Kinetic and Potential Energy

2. 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

3. 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) = .10kg Speed (v) = 8.0m/s2 KE = ½ (.10kg)* (8.0m/s)2 KE = 3.2 kg*m2/s2 = 3J

4. 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

5. Potential Energy
Potential energy is the energy stored as a result of position
Gravitational potential energy depends on an object’s height

6. 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)

7. 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

8. 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

9. 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

10. Chemical Energy Chemical energy is the energy stored in chemical bonds
The energy is released when the bonds are broken

11. Electric Energy
Electric energy is the energy associated with electric charges
Batteries contain electric energy

12. 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