Physics Flashcards
Heat gained by water is equal to
Heat lost by some element
Dynamic equilibrium occurs when?
All sum of forces acting on an object in motion is equal to zero ( the object moves but doesn’t acceleRte)
The force that acts pararallel to the surface of the incline is
Frictional force
Mgsin theta
Force acting perpendicular to the surface of incline is
Normal force
Mgcos theta
Stretching or compressing an elastic object away from its equilibrium point increases its ..
Elastic potential energy ( work must be done against it)
What happens when matter transfer from one phase to another?
It absorbs or releases heat
But the T remains the same!!!
What is entropy? S
Measures the disorder of a substance or system ( solids have the lowest then liquid then gas)
More entropy - more disorder
Kinetic energy means
Movement
Energy during combustion works by?
Storing the chemical energy and releasing it by creating new bonds with less energy
Minimum relative sped occurs
When both move in the same direction
v= difference between two speeds
Maximum speed occurs when
Both speeds move in opposite direction and v= sum of two speeds
Objects inertia is
Its resistance to changes in its velocity, object tend to stay on motion or stay at rest.
Tension is
Force experienced by a string due to opposing forces at each of its ends
What is heat?
Heat is the energy transferred between two substances with different T
Snell law light refraction
n1 sin angle1 = n2 sin angle 2
n1/n2 = sin angle 2/ sin angle 1
Refractive index depends on the ..
Speed of light
Greater index = slower speed of light
At constant speed net force Fnet equals
0
F= Ff
What is reflection? (Отражение)
Light travels in a new direction when light encounters an interface between two different media
Allows us to see objects and perceive their colors
Doppler effects occurs when
A periodic signal emitted from a source (sound, light) is perceived by an observer to have a different wavelength due to the relative motion between the source and observer.
Change of wavelength is proportional to the relative speed between the source and observer
If the source is mixing toward the observer = wavelength and signal decreases.
Away from the observer = wavelength and signal increases
An alteration in the observed frequency of a sound due to go motion of either the source or the observer. Observer month toward the source = higher frequency of sound, the person moving away from the source = lower frequency of the sound. Is the source coming toward the observer= higher frequency and vice versa
Static of equilibrium means
Gravitational force down and tension force upward
Sum of forces = 0
Cardiac output is
The amount of blood pumped out of the left ventricle in 1 min
CO = SV * HR
SV = strike volume of the heart- volume of blood pumped out in a single heartbeat ( SV = EDV - ESV end diastolic volume-end systolic volume)
HR = heart rate
Cardiac output is inversely proportional to
Vascular resistance
Inertia is directly proportional to
Mass
The force required to move a stationary object must be greater than the ..
Static friction force
Tension at constant velocity depends on
Frictional force
Work energy theorem states
Works done by a force on an object can be calculated as the change in the objects KE
Law of conservation of energy states
Total energy which is the sum of PE + KE must remain constant
During exercise blood flow to the skin increases in order to
Maintain normal body temperature through heat transfer mechanisms
Static friction definition
Frictional force that per event two surfaces from sliding.
Higher normal force = higher friction= greater stretching
Fs = u F
Difference between static friction and kinetic friction
Static = not moving
Kinetic = moving
Uk is always less than Us
Static can increase but kinetic is constant
Kinetic friction definition
Occurs when surfaces slide against each other. Moving.
Fk = Uk * F
When the velocity is positive than friction has a sign …
Negative because kinetic friction acts in opposite direction and vice versa
Perpendicular is … while parallel is ..:
Cos,
Sin
Normal force with weight
N= W cos or sin
When the normal force decreases the kinetic friction also
Decreases and vice versa because Fk = uF
Work is done by friction sliding down and up the ramp equals
W = wdown + workup
2FL
Difference between potential energy and kinetic energy
KE= motion of objects
PE= position of objects
Periodic motion is
When on object moves in a cyclical fashion returning to the same location after a certain period of time. Modeled in terms of wave motion, where time required to compete one cycle of motion and its names as a period (T) which is expressed in seconds
f = 1/T
Work energy principal
W = delta KE
W = - delta PE
KE+ PE=0
High frequency electromagnetic radiation are more … while low frequency radiation carries much less …
Energetic,
Energy
Radiation energy is directly related to ..
Temperature
Higher frequency = higher T
Lowry frequency = lower T
Enthalpy H definition
Measures energy stored in a chemical bond and is amount of energy released or absorbed from the formation and destruction of chemical bonds in a reaction.
Energy is released as heat if the H of the products is lower than H of the reactants and H is negative (exothermic).
When H of products is higher than H is positive ( endothermic)
Phase changes
Bomb cell is a type of what system? And calorimetry device?
Closed. Heat can be exchanged but matter cannot
Isolated, neither heat not matter can be exchanged
Conduction definition
Direct transfer of energy from molecule to molecule through molecular collisions. Through direct contact.
Metals are the best conductors, gases are the worst.
Convection definition
Transfer of heat by physical motion of a fluid over a material.
Only for liquids and gases.
Motion of fluids.
Specific heat of water is
1 cal/ g* K or 4 J/g*K
Phase changes occur at
A constant T since the changes in PE not KE
Energy dispersion definition
Energy goes from being concentrated to being spread out
When an object floats?
When it’s density is less than the density of the fluid.
When an object sinks?
When its density is greater than a density of fluid
The object remains suspended when
The density of an object and fluid is the same
When Zero net force is exerted on an object then the object must
Be at rest or moving at a constant velocity
Fnet = Fb + F drag -Weight = 0
State function is
Entropy and doesn’t need path to be taken
Thermodynamic equilibrium definition
Temperature of the system is constant and uniform throughout its volume and there is no flow of energy. T is the same with another system or its surroundings
Process functions definition
Describes the path taken by a state to transition from one equilibrium state to another ( work and etc)
Isothermal process means
Temperature of the system doesn’t change
Adiabatic process means
Occurs with no heat exchange between the system and the environment
Isochoric ( isovolumetric) process is
Volume of the system doesn’t change
Isobaric system is
Pressure of the system doesn’t change
Latent heat of vaporization definition
The condensation point is the T at which the phase transition from gas to liquid occurs releasing head equals to latent heat
Electron force should be directed what way?
Along the protons motion to increase its velocity
In static equilibrium when no rotational movement the torque is
Sum of all torques = 0
Inertia definition
Objects tendency to oppose changes in motion. Depends only on characteristic of an object itself (mass but not gravity or position)
Friction definition
Force that resists sliding between two surfaces
Tension definition
Force that results from an object being pulled in two directions
Velocity of light is inversely proportional to
Its index of refraction
