Chapter 9.3 Mechanical Energy

9.3 Mechanical Energy The two forms of mechanical energy are kinetic energy and potential energy.

9.3 Mechanical Energy Mechanical energy is the energy due to the position of something or the movement of something.

Mechanical Energy Total mechanical energy = kinetic energy + potential energy TME = KE + PE 100 J = 0 J + 100 J At rest, no KE, no motion 100 J = 50 J + 50 J In motion, 50 J of PE transferred, object now has 50 J of KE. 100 J = 100 J + 0 J In motion, no potential energy (100 J transferred to KE) In each case, the total mechanical energy is the same. As the PE decreases, the KE increases.

Mechanical Energy = PE + KE 100 J = 100 J PE + 0 J KE 100 J = 50 J PE + 50 J KE 100 J = 0 J PE + 100 J KE

Indicate where: KE is at a minimum and maximum PE is at a minimum and maximum The speed is greatest The speed is least

KE min KE min PE max PE max V = 0 m/s V = 0 m/s transformation of PE to KE (release) transformation of KE to PE (storage) KE max PE min V = maximum

9.3 Mechanical Energy What are the two forms of mechanical energy?