Momentum (HT ONLY) Flashcards
whats the equation for momentum?
momentum (kgm/s) = mass (kg) x velocity (m^2)
is momentum scalar or vector?
vector, as it has a magnitude and direction
what is the conservation of momentum principle?
in a closed system, the total momentum before an event is equal to the total momentum after an event
what unit is momentum?
kgm/s
what is the momentum for stationary objects?
0, as momentum requires motion
how do you change an objects momentum?
slow an object down or speed it up
what causes acceleration of an object?
a force acting on the same direction that the object is already moving in, which increases velocity so increases momentum
how do we calculate force?
force (N) = change in momentum (kgm/s) / time (s)
what is another equation for force?
force = (mv - mu) / time, where mv is the final momentum and mu is the initial momentum
why are car crashes so dangerous in ways on momentum?
when a car crashes, the momentum is immediately reduced to 0, meaning the car experiences a huge force, which could cause injuries to the people inside. to reduce injury, we need to spread the change in momentum over a longer period of time and reduce force.
how does a car in a crash lose momentum more gradually?
it has crumple zones which crumple under impact, which supplies a smaller amount of extra time for the car to lose momentum
how do air bags help you lose momentum?
they are compressable
how do seat belts help you lose momentum?
they are slightly stretchy, so you slow down a bit more slowly
