momentum Flashcards
what is the principle of the conservation of momentum?
total momentum before = total momentum after in a closed system where no external forces act
what is newtons 1st law?
an object will remain at rest or continue moving with constant velocity unless acted on by a resultant force
what does a closed system mean?
no external forces
what is the formula for change in momentum?
change in momentum = force x time
what is the formula for force?
force = change in momentum/ time
what is newtons 3rd law?
object a pushes on object b and object b pushes on object a with an equal opposite force
what 3 things must happen in order for newtons 3rd law to take place?
must be the same type of force, act on different objects and act in different directions
what is the formula for change in momentum? (momentum)
final- initial
what are the 4 key points for safety?
1) write equation
2) increase time taken to stop
3) to change the same momentum the force needs to be smaller as time is greater
4) prevents injury
what is momentum measured in?
kgm/s
is momentum a scalar or a vector?
vector because it has magnitude & direction
what does the + or - sign show with a momentum value?
the direction
what does the value of the momentum show?
the magnitude
what does a + sign show for the momentum?
the direction is up or right
what does a - sign show for the momentum?
the direction is down or left
what equipment is needed for the investigation of momentum?
- linear tracks with 2 carts
- light gates, interface & computer
- electronic balance
- pasco file 1.05
what do forces cause objects to do?
- change shape
- change speed
- change direction
what is the formula for resultant force?
resultant force = mass x acceleration
why does Newton’s third law apply to the conservation of momentum?
it is Newton’s third law pairs that cause the momentum to change
what is change in momentum also called?
impulse
to change momentum over a longer time…
a smaller force is needed
to change momentum over a shorter time…
a larger force is needed
how do crumple zones prevent injury?
- force = change in momentum/ time
- crumple zones increase the time taken to stop
- to change the same momentum, the force needs to be smaller as time is greater
- prevents injury
the conservation of momentum always applies when…
no external forces act
