Week 1 Day 3 - Physics Flashcards
Is Q > 0 or is Q < 0 in an exothermic process?
Q < 0, energy flows out of system (system appears hotter)
Q = energy put into the system (makes sense that value is less than 0 if energy is flowing out of the system)
What does pressure measure?
force per area pounds / square inch
In an endothermic process, is Q > 0 or is Q < 0?
Q > 0, energy flows into the system ( system appears colder than environment) Q = energy put into the system
What is heat?
process of energy transfer caused by a difference in temp
Density of H20
1 g/ml 1 ml of H20 has a mass of 1 g
When work is done on the system (by the surroundings), is W > 0 or is W < 0?
W > 0, compression W= work done on the system
scalar
have magnitude and units, but not direction
What is a manometer and how does it work?
used to measure pressure differences compares atmospheric pressure to unknown pressure U shaped tube, filled with a fluid of known density, the height difference of the fluid in the two arms indicates pressure difference
An object at rest or moving at constant speed in a straight line will continue in that state until a net external force acts upon it
Newton’s 1st law
weight
measure of force (weight);
measured in N
force = m * a
weight = m * a
weight = m * g, where g is the force of gravity (9.8m/s^2)
What is work?
result of a force acting through a distance
you are not working if object doesn’t move or moves in the wrong direction
W = Force (N) * d (m)
kinetic energy + potential energy =
the total energy of the system
aneroid bellow gauge
use expansion of bellows by pressure
measure pressure without the use of fluid
great for measuring low pressures i.e. BP
When the system is doing work (on the surroundings) , is W < 0 or is W > 0?
W < 0, expansion
W=work done on the system
Units of work
N * m
1 N * m = 1 J (Joule) = 1 kg*m2/sec2
mass
amount of matter in an object
resistance to acceleration
measured in: kg
acceleration
change in velocity per time
how velocity changes with each second of time
measured: m/s2 (meters per second per second)
Which is the weakest fundamental force?
gravitational force
the force between all matter holds earth in sun’s orbit and keeps you from floating away
1st law of thermodynamics
‘delta U’ = Q + W
change in internal energy = energy put in the system (Q) + work done on the system (W)
It’s not possible to reach absolute zero
3rd law of thermodynamics
What is kinetic energy?
the energy a mass possesses by virtue of being in motion
i.e. car going down the highway
velocity
change in location/change in time
more detailed: displacement or change in location/ time
interval over which the change takes place measured in: m/s
For every action, there is an equal and opposite reaction
Newton’s 3rd law
T of F: Mass is a scalar.
True. Mass has magnitude and units, but no direction
What is potential energy?
stored energy i.e. compressed gas, chemical bonds
vector
have magnitude, units, and direction
Electromagnetic force
holds electrons in atoms tries to force protons apart (but cannot because the strong nuclear force is stronger)
Heat flows from hot to cold
2nd law of thermodynamics
Units for energy
Joules *units for energy and work are the same*
Velocity is a ______ while speed is a ______.
vector: scalar
speed involves distance while velocity involves displacement (distance + direction)
Heat is a measure of ________.
energy
Power
rate of work work/time
measured in Watts
1 Amp * 1 Volt = 1 Watt
specific gravity of H20
1
What is internal energy in the equation: ‘delta U’ = Q + W
‘delta U’ = change in internal energy
internal energy is the total of the kinetic and potential energies of the molecules in an object
Is weight a vector or scalar?
vector
formula for specific gravity
density of substance (g/ml)/ density of water (g/ml)
spec grav is unitless
bourdon gauge
use coiled tube that “straightens” in response to pressure, causing the pointer to mover around a numerical scale great for measuring really high pressure
A and B are in thermal equilibrium if they have the same temperatures
'’0” law of thermodynamics
Is distance a scalar or vector?
scalar
Newton’s 2nd law
force = mass * acceleration
What is a barometer and how does it work?
device used to measure atmospheric pressure
compares atmospheric pressure to a vacuum
the height of a column of fluid (typically mercury) is a direct measure of atmospheric pressure
Which is the strongest fundamental force?
strong nuclear force (has a short range) - holds protons and neutrons in nucleus
