CHAPTER 3 AND 4: FINALS REVIEW Flashcards
What is energy?
The ability to do work or cause change
What are the different forms of energy?
- Electrical energy (energy caused by the ordered movement of electrons from one atom to another)
- Thermal energy (energy cause by the movement of particles)
- Radiation energy (energy stored in electromagnetic waves)
- Chemical energy (energy stored in molecular bonds)
- Wind energy (caused by the movement of air)
- Sound energy (energy stored in sound waves)
- Hydraulic energy (caused by the flow of water)
- Nuclear energy (energy stored in atomic nuclei)
- kinetic energy (energy of an object in movement)
- potential energy (energy an object could have based on mass and position )
what does W= F//D mean
work = force x distance
What does 1J equal to?
1Nx1m
What’s the difference between an energy transfer and an energy transformation?
Energy transfer: energy going from one place to another
vs
Energy transformation: energy changing from one form to another
What are the differences between opened systems, closed systems, and isolated systems?
Opened system: allows matter & energy in and out
Closed systems: allows matter and energy in but not out
Isolated system: does not let matter in nor out
When dealing with open systems, much of the energy is lost. If you had to calculate the energy efficency of a car, what formula would you use?
EE= (useful energy/total energy consumed) x 100
What is the law of conservation of energy?
- No energy is created nor lost, everything is simply tranferred or transformed
- The energy in an isolated system will always remain constant
What factors affect thermal energy?
More thermal energy: - More particles - Higher temperature Less thermal energy: -Less particles -Lower temperatures
What is the principle of heat?
Thermal energy will transfer from a hotter place to a colder place until both places are the same temperature
How would you calculate the relationship between heat and thermal energy?
Q=ΔEt
Q= heat (J)
ΔEt= variation in thermal energy (J)
What is the difference between heat and temperature?
Heat: the transfer of thermal energy
Temperature: The measure of the degree of agitation of the particles in a substance
What is specific heat capacity?
the amount of thermal energy needed to raise 1g of a substance by one degree celsius.
What is the specific heat capacity of water?
4.19J/°C
How do you calculate thermal energy?
Q=mcΔT Q = thermal energy (J) m= mass (g) c= specific heat capacity (J/°C) ΔT= variation in temperature
How would you calculate kinetic energy?
Ek= 0.5mv^2 Ek= kinetic energy (J) m= mass (kg) v= velocity in m/s
When the velocity of an object doubles…
Ek quadruples
How would you calculate gravitational potential energy?
Ep=mgh Ep= graviatational potential energy (J) m= mass (kg) g= gravitational field intensity h= height (m)
What is Mechanical energy? How would you calculate it?
The sum of Ek and Ep
Em= Ek+Ep
Emi=Emf
The law of conservation of energy states that in a frictionless system…
Em remains constant
What is force?
- Force is the factor which changes the motion or shape of an object through pushing and pulling.
- It is always represented by an arrow or a vector
- It accelerates or decerlerates an object as well as change its tradgectory
Force is represented in N, therefore…
F = N = kg x m/s^2
Gravitational force (fg) is the attraction between two bodies on account of their masses and the environment’s gravitational constant (acceleration of all free falling things regardless of mass). Therefore…
Fg = mg Fg= gravitational force (N) m= mass (kg) g= gravitational constant/field intensity
Speed is affected by the amount of distance over a certain time period. Therefore…
v= d/Δt v= velocity (m/s) d= distance (m) Δt= variation of time (s)
