Physics Flashcards
How do you convert from cm to m?
divide by 100
what are the units for energy?
Joules
How do you convert oC into K
+273
What is work done
the energy transferred from one store to another
In the equation for work done
Delta W = F x Delta s
What does F stand for?
Force
In the equation for work done
Delta W = F x Delta s
What does Delta s stand for?
change in displacement
In the equation for work done
Delta W = p x Delta V
What does p stand for?
pressure
In the equation for work done
Delta W = p x Delta V
What does Delta V stand for?
Change in volume
what is the equation for kinetic energy?
0.5 x mass x velocity squared
what is the equation for elastic energy?
0.5 x spring constant x extension squared
what is the equation for gravitational potential energy?
GPE= gravity x height x mass
what is the definition for power?
power is the amount of energy transferred per second
what is the equation for power?
power = work done divided by time
or
power = energy transferred divided by time
what is the equation for pressure?
pressure= force divided area
described what the origin of gas pressure is
particles that have a lot of kinetic energy causes the particles to collide which exerts a force on each other and on the container
In the ideal gas equation:
pV = NkT
What does T stand for?
temperature
In the ideal gas equation:
pV = NkT
What does N stand for?
number of particles
In the ideal gas equation:
pV = NkT
What does V stand for?
volume
In the ideal gas equation:
pV = NkT
What does p stand for?
pressure
what is the equation for Boyles law?
pressure x volume = constant
what is thermal equilibrium?
when all states within a system are at the same temperature
define temperature
the measure of average kinetic energy of particles
The formula for energy transferred when a substance changes temperature is given by:
Delta Q = m x c x Delta T
What does Delta T mean?
change in temperature
The formula for energy transferred when a substance changes temperature is given by:
Delta Q = m x c x Delta T
What does c mean?
specific heat capacity
The formula for energy transferred when a substance changes temperature is given by:
Delta Q = m x c x Delta T
What does Delta Q mean?
change in heat or energy transferred
The formula for energy transferred when a substance changes temperature is given by:
Delta Q = m x c x Delta T
What does m mean?
mass
In the equation for energy transferred when a substance changes state:
Delta Q = m x L
What does L stand for?
Specific latent heat
What is the definition for specific heat capacity?
the energy required to change the temperature of 1 kg of substance by 1K
what is the definition of specific latent heat ?
the energy required to change state of 1kg of substance
What is Latent fusion?
Change of state between solid and liquid e.g melting and freezing
What is latent vaporisation?
Change of state between liquid and gas e.g boiling and condensing
What is internal energy?
the sum of kinetic and potential energy of particles
In the equation for the first law of thermodynamics:
Delta U = Q - W
What does W mean?
work done by the system
In the equation for the first law of thermodynamics:
Delta U = Q - W
What does Q mean?
Heat added to the system
In the equation for the first law of thermodynamics:
Delta U = Q - W
What does Delta U mean?
Change in internal energy
What is an adiabatic reaction? (3 factors)
no net transfer of heat -
Q = 0
Fast process
What is an isothermal reaction? (3 factors)
constant internal temperature
slow temperature change
Q = W
What does the 2nd law of thermodynamic state?
entropy (measure of disorder) always increases
The diagram shows a carnot cycle
Label 4 –> 3
adiabatic compression
The diagram shows a carnot cycle
Label 1 –> 4
isothermal compression
The diagram shows a carnot cycle
Label 2 –> 1
adiabatic expansion
The diagram shows a carnot cycle
Label 3 –> 2
Isothermal expansion
What does boyles law state?
that N and T are constant and that P and V are constant
What is the definition of elasticity?
the ability for an object to stretch and return back to its original state once the force is removed
What does Hooke’s Law state?
states that force and extension are directly perportional
In the equation for Hooke’s law?
F = k x Delta x
What does k mean?
Spring constant
In the equation for Hooke’s law?
F = k x Delta x
What does F mean?
Force
In the equation for Hooke’s law?
F = k x Delta x
What does Delta x mean?
Extension or change in length
How can you tell from a graph that a material is obeying Hooke’s law?
The line is straight
For a force-extension graph what does the gradient show?
shows the spring constant
For a force-extension graph what does the area below the graph show?>
Shows how much work is being done
On the graph what does point E label?
breaking point
On the graph what does point B label?
elastic limit
On the graph what does point A label?
limit of proportionality
Define stress?
The force per unit area of a material
What is the equation for stress?
stress = force / cross sectional area
What is the unit for stress?
N/M2
Define strain?
extension per unit length
What is the equation for strain?
extension / original length
What is the unit for strain?
no unit
What is the equation for young’s modulus?
E= stress / strain
Define young’s modulus?
measures stiffness of the material (stiffness constant)
Look at the stress/stress diagram. Which line represents a elastic material
C
Look at the stress/stress diagram. Which line represents a brittle material
B
Look at the stress/stress diagram. Which line represents a ductile material
D
What does the gradient represent on the young’s modulus
it represents how stiff the material is
Up to what point of the youngs modulus apply to ?
the limit of proportionality.
Define brittle?
hard but liable to break (little or no plasticity)
Define ductile?
the ability to be shaped by plastic flow under tension
Define creep deformation?
slow version of plastic deformation but at a high temperature
Define malleable?
ability to be shaped by plastic flow under compression
Define fatigue?
weakness in a metal or other materials caused by repeated variations of stress
Define ultimate tensile stress?
highest stress a material can sustain just before it breaks
Define yield strength?
The stress at which plastic deformation starts
Define density?
amount of substance per unit volume
In the equation for density
p = m / V
what does V stand for? What are the units?
volume, m3
In the equation for density
p = m / V
what does m stand for? What are the units?
mass, kg
In the equation for density
p = m / V
what does p stand for? What are the units?
density, kg/m3
Define fluid
a substance that has no fixed shape and yields easily to an external force
Describe a laminar flow?
- parallel path flows -slow and constant -less air resistance
Describe a turbulent flow?
-irregular flow -fast but inconsistent -more air resistance
Describe viscosity?
the state of being thick, sticky, and semi-fluid in consistency
What is the unit for viscosity?
kgm-1s-1
What are the 3 factors that affect viscosity?
-temperature -molecular structure -pressure
How does temperature affect viscosity of a liquid?
as temp increases the viscosity of the liquid lowers as it becomes easier for molecules to slide past each other
how does temperature affect a gas?
the increase in kinetic energy created collisions
What are newtonian fluids?
-predictable response to force -consistent viscosity
What are non-newtonian fluids?
-unpredictable response to force -inconsistent viscosity
Describe diliant (shear-thickening) how does the viscosity change?
changes viscosity when a force is applied viscosity rises with a rise in shear strain
Describe pseudoplastic (shear-thinning) how does the viscosity change?
when you apply a force it gets thinner viscosity decreases with a rise in shear strain
Describe rheopectic how does the viscosity change?
-time dependent when applying stress fluid gets thicker when no stress it starts to get thin -more viscous when stressed
Describe thixotropic how does the viscosity change?
-fluids thin gradually on stirring then slowly reset -less viscous overtime when stressed
Describe Bingham plastics how does the viscosity change?
-behaves like a solid at low stress but above a yield stress they begin to flow -solid at low stress and as a viscous fluid at higher stress
How do you convert from MW to W?
x 1000000
How do you convert from km to m?
/ 1000
How do you convert from mW to W?
/ 1000
How do you convert from GJ to J?
x 1000000000
What is the unit for power?
Watts
What is the unit for work done?
Joules (J)
Name two units for pressure?
Pa and N/m2
What is the unit for force?
Newton (N)
What three factors affect gas pressure?
temperature, volume of gas and number of particles
In which state do particles have the most kinetic energy?
gas
In which state do particles have the least kinetic energy?
solid
In which state do particles have the most internal energy?
gas
In which state do particles have the strongest intermolecular forces?
solid
