momentum Flashcards
momentum
the property of any moving object
momentum equation
mass x velocity
momentum 1 object - how to change its momentum
to change an objects momentum you can either:
change the mass (eg snowball gathers snow as it rolls down a hill)
or usually change its velocity
momentum - scalar or vector
vector - size +direction
size of force needed to change an objects momentum
depends on the time over which the change occurs
force to change momentum equation
f = change in momentum / time
f = mv-mu/t
crumple zones / air bags / seat belts / bending knees
- increase TIME of collision
- decreases the RATE of change of momentum
- so there is a lower force on a person (PREVENTS INJURY)
what reduces the force to change an objects momentum
crumple zones / air bags / seat belts / bending knees
the law of conservation of momentum
the TOTAL momentum BEFORE objects collide/interact is = to the TOTAL momentum of the objects AFTER
(assuming no external forces act)
types of collision
- hit and go one direction
- stick together
- explode away from each other
hit and go one direction collision
take into account direction
- stick together collision
ADD masses if they stick together
explode away from each other collision
- the total momentum before = 0
- to obey the law of conservation of momentum must be 0 after
- so one object gains forward momentum (+) and the other gain backwards momentum (-)
