m
units : Kg M/s
· .
consider Newtons 2nd Law Emman
>
-
Fnet ma =
inemd
-
dt
:
>
-
Fret
we can also relate to KE :
1 = mr2 : Em =
Section 7 2
.
↑ can
change due to changing ,
which is an ,
which is caused by F
·
the impulse is change in momentum due to a force :
J :
AF =
SE(t) at
Often we don't know howI depends on time.
·
we can find I in terms of Fave :
T ap FaveAt
= =
Section 7 3 .
by Newtons 3rd Law :
·
Fiz Ez
= -
mi Maz =
= d -
at
It
when 2 objects interact their individual momenta change but total momentum is constant
·
, ,
therefore , in a closed system, total momentum is conserved
·
this is called law of conservation of momentum.