Download Exam 2 Review - BYU Physics and Astronomy

Exam 2 Review
Jerika McKeon
You will need your CID for the examMemorize it!!!!!
Announcements
 Other Reviews:
 Tomorrow @ 5:30-7pm
 Friday @1-3pm (weekly) 108 MARB
 Check to see if you are missing any FBD scores.
 If you are, check the boxes to see if you put the wrong CID.
 Turn it back into the 105 Appeals box.
 I’m behind on extra credit, but I will grade it. Don’t worry
about sending me an other copy. I will email you once your
extra credit is in Max.
Energy
 Kinetic Energy
 Conservation of Energy
 Potential Energy
 Work-Energy Theorem
 Gravitational PE
 Spring PE
 Work
 W=change in energy
 W=F//d
 Work lost by friction
 Power (NOT IN
SYLLABUS)
 P=ΔE/Δt
 Collisions
 Elastic
 Inelastic
 Perfectly Inelastic
Energy Cont.
Kinetic Energy
 Linear KE
 KE=1/2*m*v^2
 Rotational KE
 1/2*I*ω^2
 Depends on moment of
Inertia (we’ll talk about
that in a minute)
Potential Energy
 Gravitational PE




PE=mgy
PE=-GMm/r
PE=0 at r=∞
Escape velocity equations
 Spring PE
 F=-kx
 PE=1/2*k*x^2
 Always positive (for both
compressed & stretched
springs)
Linear Momentum
 p=mv
 Conservation of momentum- When is this true?
 Impulse=Ft
 FΔt=Δp
Collisions
Elastic
Inelastic
 Energy is conserved
 Inelastic
 Conservation of
momentum and
conservation of energy
 Can use the velocity
reversal equation
 Usually you will use 2
equations and make some
substitutions to get your
answer
 Energy is not conserved
 Use conservation of
momentum
 Perfectly Inelastic
 Energy is not conserved;
Max energy is lost
 Objects stick together
 Use conservation of
momentum
Conservation of Energy
 Ei+Wnet=Ef
 Wnet
 Energy lost from friction
 Energy gained through other forces
 Photogate problem!
Angular Stuff
 Angular Kinematics
 Δθ=θf – θi
 ω=Δθ/Δt
 α=Δω/Δt
 Other kinematics equations
 Conversions- all θ must be in radians
 s=rθ
 v=rω
 a=rα
Moment of Inertia
 Analogous to mass
 Depends on how the mass of an object is distributed
 I=mr^2 for point mass
 I=other stuff for other shapes
Angular Momentum & KE
 Angular momentum
 Li=Lf
 L=Iω
 L=rp (hidden angular momentum)
 KE=1/2*I*ω^2
Torque
 Pivot Points
 T=rF
 Tnet=Iα
 Sum of Torques just like sum of Forces
 Counterclockwise = positive
 Clockwise = negative
 Equilibrium = no angular or linear acceleration
 Tnet=0
 Fnet=0