Week 1 Day 3 Flashcards
Newton’s Laws
- An object in motion stays in motion (or rest) until acted upon by external force
- F= m*a
- for every action there is an equal and opposite reaction (picture the gun or cannon with recoil)
Mass
(kg)
m = F/a
amount of an object = resistance to acceleration
Velocity
(m/sec)
v = Âx/Ât
change in location per time
Acceleration
(m/sec2)
a = Âv/Ât
change in velocity per time
Force
(kg*m/sec2)
F = m * a
Push or pull needed to accelerate a mas
Scaler
has magnitude and units, no direction
distance, speed, mass
vectors
magnitude, units, and direction
displacement, velocity, weight
Stron nuclear force
(strongest force)
holds protons and neutrons together in nucleus
electromagnetic force
holds electrons in atoms, tries to force protons apart
gravitational force
(weakest)
holds earth in suns orbit and us from floating away
Gravity
All matter is attracted to all other matter with the force:
F = G * m1 * m2 /r2
G is the gravitational constant (a universal value)
m1 and m2 are the masses of the two objects
r is the distance between them.
g
≈9.8 m/sec2
weight
W = m * g
Density
mass/volume
1 ml water has mass of 1 g so the density of water is 1 g/ml
specific gravity
the density of a substance divided by the density of water (1g/ml)
-unitless
Pressure
P = F/ area
ex. pounds per square inch (PSI)
Barometer
Compares atmospheric pressure to a vacuum
Patm = p * g * h
p = density of the liquid
Manometer
compares atmospheric pressure to an unknown pressure
ÂP = p * g * Âh
aneroid bellow gauge
Use expansion of bellows by pressure
Bourdon Gauge
Use coiled tube that “straightens” in response to pressure
work
(joule) kg*m2*sec2
the result of a force acting through a distance
*if you push something (against a force) and it moves.
W = F(N) * d (m)
F= applied force
N= newtons
d= distance
m= meters
Joule
N*m
or
kg * m2/sec2
measure of work
Kinetic energy
energy a mass has because it is in motion.
Potential energy
energy stored because of its position
Internal energy
KE + PE of molecules
ÂU=Q+W
Calorie
unit of Energy
1 calorie = the energy needed to increase temp of 1 g of H2O 1°C
Power
Watt or J/sec
the rate of work
work/time
Law of thermodynamics
0) two systems are in thermal equilibrium if they have the same temperature
1) ÂU = Q + W, change in internal energy = energy put into system = work done on the system
2) Heat flows from hot to cold
3) Its not possible to reach absolute zero
ÂU
change in internal energy
Q
energy put into the system
W
work done on the system
endothermic process
Q > O
energy flows into the system
(the system appears colder than environment)
exothermic process
Q < O
energy flows out of the system
(system appears hotter than the environment)
Work done by the system
W < O
expansion
*the pressure of the system pushes the plunger back up
work done on the system
W > O
compression
(pushing plunger down)
heat
energy that is transferred as result of temperature difference
*can be viewed as an energy flow or a process
Watt
J/sec
kg*m2*sec3
measure of power
Pascal
N/m2
