36-39 Flashcards
displacement
the final position minus starting position (NET DISTANCE, not individual distances)
total distance is often greater
velocity
displacement / time
Velocity is a Vector that specifies SPEED and DIRECTION
if displacement is 0 then velocity is 0 (IMPORTANT)
speed
the speed of your car, a Scalar
velocity cannot exceed speed
assume all collisions are inelastic, unless otherwise specified
TOTAL MOMENTUM IS ALWAYS CONSERVED, KE is SOMETIMES conserved
for elastic, KE is conserved
subatomic particles are elastic collision
heat transfer equation
kA (Ti - Tf) / L
A = Area L = thickness
isobaric
work done is the area (pay attention to arrow)
W = P * ∆V
∆E = Q - P∆V
adding Q increases expansion of the gas
∆E = Q - W
Q is positive when heat moves into the system
W is positive when work is done to the environment
isothermal
Q = W (an isotherm)
∆E = 0 (no change in internal energy)
adiabatic
no heat is transferred, all energy is transferred as work
a rapidly expanding gas drops pressure and cools; but no heat is exchanged
Q = 0
∆E = -W
the system loses energy
isochoric
same volume; ∆E = Q
work is 0 because volume is constant!
conduction
hot sand transfers heat by touching; radiation is by sun
conDuction = “damn that was hot”
convection
flow of heat in gases and fluids
if an object’s density is 3/4 the density of fluid…
3/4 will be submerged
Bernoulli assumptions
- incompressible
- no viscosity
- laminar flow
- steady flow
torricelli’s result
v = (2gD)^.5
you have to 4x height to double the flow rate
