Beginner's Momentum Flashcards
what is newtons second law, very simply
F = ma
what equation shows the link between the force applied to a single body and its momentum
- a = (v - u) / t
- or just a a = delta v / delta t
what equation would you get from substituting the a in f = ma for the equation for acceleration
- F = m(v - u) / t
- giving you F = (mv - mu) / t
what would that derived equation be in words
resultant force = change in momentum / time interval
how would you arrange the change in momentum equation to calculate the change in momentum itself
Ft = (mv - mu)
what is Ft called and what are its units
- it is called the impulse of a force
- given the units Ns
what does that equation with Ft now tell us
- that the impulse of the force is equal to the change in momentum of a mass
- when it is subjected to a resultant force
if two ice skaters, a man and woman, were pushing away fro each other horizontally how would their momentum compare
- the change in momentum of the woman would be equal and opposite to the change in momentum of the mans
- this is because of the conservation of momentum
- stating that the momentum before an event must equal the momentum after an event
what do equal and opposite changes in momentum imply about the impulse forces of the man and woman
that the impulse force on the woman must also be equal and opposite to the mans
how could you formulaeically show that the impulse of the forces are equal and opposite for the man and woman
- F(w)t = -F(m)t
- when cancelling out the time interval
- F = -F
- giving you equal but opposite forces
what does this also further prove and why
- newtons third law about reaction force
- he stated that when a force is applied on an object it will apply and equal and opposite force (same force in the opposite direction)
- also called the reaction force
- F = -F shows this
what is the event of the two skaters pushing one another apart an example of
recoil
