Mechanical Energy

• Energy - ability to do WORK
• Work - the product of force and displacement.
• Work Formula

  W= Fd

  unit: N.m

  positive, negative, or zero work
• Mechanical Energy - energy that is transferred when work is done.
• Types of mechanical energy

  A) Kinetic Energy

  B) Potential Energy

  C) Gravitational Potential Energy

  D) Elastic Potential Energy

  
• Kinetic Energy - energy in motion
• Kinetic Energy

  Unit is Joules (J) or kg m2 / s2

  Formula - K.E. = 1/2 m v2
• Gravitational Potential Energy - It is a function of an

  object’s height
• Unit is Joules (J) or kg m2 / s2

  Formula - GPE = mgh
• Elastic Potential Energy - It is an energy stored in elastic substances or objects
• EPE

  Formula - EPE = 1/2 kx2
• Type of Energy

  EPE

  
• Type of Energy

  GPE

  
• Type of Energy

  KE

  
• Type of Energy

  GPE

  
• Law of Conservation of Mechanical Energy:

  The total KE and PE of a system is always constant throughout its

  motion.
• TME

  A) KE + PE

  
• What happens to raindrops

  Loses potential energy and gains kinetic energy.
• A stone rolls down some distance and gains 45 J of kinetic energy. Neglecting friction, how much gravitational potential energy did the stone lose?

  GPE = 45J