Work, Energy and Power Flashcards
what is mechanical energy?
- kinetic energy (movement)
- potential energy (position)
what are the units for energy and the base SI units?
conduct dimentional analysis on kinetic energy and gravitational potential energy to show they are both equations of energy
when is mechanical energy conserved?
include equation
if the only force acting on a body (doing work) is weight
what are dissipative forces?
eg: friction and air resitance
* loss of mechanical energy in the form of heat/ sound
cannot be recovered
what are conservative forces?
eg: tension/ gravity
* can be recovered
* eg: potential energy gained moving up a hill and then regiang in form of kinetic energy
what is work done?
(component of force in direction of movement) × distance
work is only done when there is movement
what is the work energy principle?
formula
what is the work done when a force acts perpendicular to it’s line of action?
ZERO
no componenet parallel to line of action
what are the two formulae for power?
assumption that work is being done at a constant rate
how do you convert units like horsepower in the calculator?
- options
2 . convert and use arrows
1 horse power = 33000 foot pounds per minute
why may energy methods be the only way of solving a problem?
acceleration may not be constant and so suvat is not applicable
What are the two power formula?
Not resultant force but driving force from the engine
Whole system type
