calculate change in momentum of the body. formula change in momentum =m(v_u)
Answers
Answer:
There are two possible ways depending on the problem.
1) The change in momentum of an object is its mass times the change in its velocity.
Δ
p
=
m
⋅
(
Δ
v
)
=
m
⋅
(
v
f
−
v
i
)
.
v
f
and
v
i
are the final and initial velocities. Remember to use the right signs when substituting
v
f
and
v
i
Example) A 3kg mass initially moving 4m/s to the right rebounds off of a wall and begins travelling to the left at 2m/s.
Taking "right" to be the positive direction:
v
i
=+4m/s,
v
f
= –2m/s, and m=3kg. Substituting,
Δ
p
=
3
k
g
⋅
(
−
2
m/s
−
4
m/s)
=
−
18
kg m/s
2) The change in the momentum of an object can also be found by considering the force acting on it. If a force,
F
, acts on an object for a time,
Δ
t
, the change in the objects momentum is
Δ
p
=
F
⋅
Δ
t
.
Remember to use the right sign when substituting
F
. For example, a force to the left could be negative.
Lastly, if your object is moving both horizontally and vertically then
Δ
p
has a vertical and horizontal component. If this is the case, the above equations still work for each component separately, Ex) To find the horizontal component of
Δ
p
use the horizontal component of
v
i
,
v
f
or
F
in the above equations.