Physics Final.pdf - Physics Final Exam Review Chapter 10...

Physics Final Exam Review
Chapter 10: Work, Energy, and Simple Machines
● Work: the process of changing the energy in a system
○ Scalar Quantity
○ Force and displacement must be parallel
- No work → no motion, perpendicular force and displacement
○ Unit: Joule (J)
○ 1 Joule=1 Nm
● Power: the amount of energy transferred in a unit of time (rate at which
work is done)
○ Unit: Watt (W)
● Positive work increases the energy in a system; negative work decreases it
● Two people apply the same force for the same distance in different
amounts of time. Their work will be the same and their power will be
different
Chapter 11: Energy and its Conservation
● Forms of Energy
○ Kinetic Energy : an object’s energy due to motion
○ Potential Energy : the energy stored in an object due to its state,
position, or form → W= Δ PE
- Examples: compressing spring, stretched rubber band, drawn
bow and arrow

○ Gravitational Potential Energy : potential energy of an object due to
its position above the reference level
- Reference Level : location at which PE is chosen to be zero
■ Height is positive above it and negative below it
○ Mechanical Energy : the sum of the kinetic and potential energy in a
system
● Work-Energy Theorem : work done on an object is equal to the change in
kinetic energy → W = Δ KE
○ Negative work=decreasing KE
○ Positive work=increasing KE
- If an object starts from rest, W=KEf
- If an object comes to rest, W=-KEi
● Law of Conservation of Energy : in a closed, isolated system the total energy
remains the same
○ Closed : nothing enters or leaves
○ Isolated : no external forces
○ KEi+PEi=KEf+PEf
Chapter 12: Momentum and its Conservation
● Momentum : product of an object’s mass and velocity
● Impulse : the product of the average force on an object and the time interval
over which it acts; vector
● Impulse-Momentum Theorem: the impulse of an object is equal to the
change in momentum → I= Δ P
●