Momentum
• The strength of an object’s motion.
• Momentum is NOT a force.
This cement truck has a lot
of momentum. It does not
HAVE force, but it could
exert a lot of force!
Momentum
• Depends on the mass and velocity of the
object.
• P = mv
where, p = momentum
m = mass
v = velocity
• Typically measured in g m/s or kg m/s.
Law of Conservation of
Momentum
• The total amount of momentum before and
after a collision is always the same.
• Momentum is transferred between the
colliding objects.
A car with a mass of 1200kg is
moving at 25.0m/s. It collides
head-on with a 1500kg car at rest.
1) How much momentum did the first car have
before the collision?
2) How much momentum did the second car have
before the collision?
3) What is the total amount of momentum of the
two cars before the collision?
4) What is the total amount of momentum of the
two cars after the collision?
5) If the first car transfers all of its momentum to
the second car, how fast will the second car be
traveling after the collision?
Check Up - Momentum
1. Which has more momentum, a baseball or
a bowling ball?
a)
b)
c)
d)
Baseball
Bowling ball
They have equal momentum
Can’t tell from information given
d) Can’t tell from information given
Momentum depends on the mass AND
velocity of the object. If you do not know
the velocity of each ball, you don’t know
which has the greater momentum.
Check Up - Momentum
2. How could a baseball have more
momentum than a bowling ball?
a) Make the baseball move faster than the
bowling ball.
b) Make the bowling ball move faster than the
baseball.
c) Make the two balls move at the same speed.
d) Make both balls be at rest.
a) Make the baseball move
faster than the bowling ball.
If the baseball, with the smaller mass, is
moving faster than the bowling ball, with
the greater mass, the two objects could
have the same momentum.
m
v
=
mv
ALSO:
d) Make both both balls
be at rest.
If both balls are at rest, neither one
has any momentum.
m0 =
m0
0 = 0