P
mv
P
(16 lbm) 22
ft
sec
P
352
ft lbm
sec
F
ma
a
(v
vo)
(t
to)
F
m
v
vo
t
to
F
mv
mvo
t
to
F
P
Po
t
to
F
P
t
MOMENTUM PRINCIPLES
Force and Motion
CP-03
Page 6
Rev. 0
Solution:
Force and Momentum
There is a direct relationship between force and momentum. The rate at which momentum
changes with time is equal to the net force applied to an object. This relationship comes directly
from Newton's second law of motion, F = ma. This is a special case of Newton's second law for
a constant force which gives rise to a constant acceleration. The linking fact is that acceleration
is the rate at which velocity changes with time. Therefore, we can determine the following:
We know that,
and since,
then,
(3-4)
which can also be written,
(3-5)
Substituting P for mv and P for mv ,
o
o
or
(3-6)
From Equation 3-6, we can determine that force (F) is equal to the change in momentum per
time.
