Mechanical Energy

1
Chapter 9.3

• Mechanical Energy

2
9.3 Mechanical Energy

• The two forms of mechanical energy are kinetic
  energy and potential energy.

3
9.3 Mechanical Energy
Mechanical energy is the energy due to the
position of something or the movement of
something.
4
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.

5
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
6

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

7
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
8
9.3 Mechanical Energy
What are the two forms of mechanical energy?