2013-3-1 Review:Mechanical Concepts of Energy >Kinetic energy,KE:The energy that a system possesses as a result of its motion relative to some reference frame. >Potential energy,PE: The energy that a system possesses as a result of its elevation in a gravitational field >Both are extensive properties of the body Earth's surf 2-7 Change in Kinetic Energy The change in kinetic energy is associated with the motion of the system as a whole relative to an external coordinate frame such as the surface of the earth. For a system of mass m the change in kinetic energy from state 1 to state 2 is AKE=KE2-KE=mV2-VP)(Eq.2.5) where -V and V,are the initial and final velocity magnitudes -The symbol A denotes:final value minus initial value. 2-8 2013-3-1 4 ¾ Kinetic energy, KE: The energy that a system possesses as a result of its motion relative to some reference frame. ¾ Potential energy, PE: The energy that a system possesses as a result of its elevation in a gravitational field. ¾ Both are extensive properties of the body 2-7 Review: Mechanical Concepts of Energy where - V1 and V2 are the initial and final velocity magnitudes - The symbol Δ denotes: final value minus initial value. Change in Kinetic Energy ►The change in kinetic energy is associated with the motion of the system as a whole relative to an external coordinate frame such as the surface of the earth. ►For a system of mass m the change in kinetic energy from state 1 to state 2 is 2-8 ΔKE = KE2 – KE1 = ( ) 2 1 2 V2 V 2 1 m − (Eq. 2.5)