Inelastic Collisions

1
Inelastic Collisions
2
Inelastic Collisions
Momentum mv Kinetic Energy Gravitational
Potential Energy Elastic Collision A
collision in which the objects do not deform or
stick together. Kinetic energy is
conserved. Completely Inelastic Collision A
collision in which the objects stick together.
Kinetic energy is not always conserved. Momentum
is conserved.
3
Railroad Cars Revisited
A 10,000kg railroad car traveling at a speed of
24.0m/s strikes an identical car at rest. If the
cars lock together as a result of the collision,
what is there speed afterward?
For the completely inelastic collision of two
railroad cars we found that the speed of the cars
after the collision was 12.0m/s. What was the
loss in kinetic energy?
Before
4
Railroad Cars Revisited
For the completely inelastic collision of two
railroad cars we found that the speed of the cars
after the collision was 12.0m/s. What was the
loss in kinetic energy?
Before
After
of energy is transformed.
5
Ballistic Pendulum
Demo
6
Ballistic Pendulum
In a Ballistic Pendulum a mass m is shot into a
capturing device of mass M with a velocity v.
Masses m and M rise to a height h. What is the
relationship between v and h?
Divide the problem into two problems, 1) the
collision, and 2) the rising of the masses.
1) Momentum is conserved.
7
Ballistic Pendulum
In a Ballistic Pendulum a mass m is shot into a
capturing device of mass M with a velocity v.
Masses m and M rise to a height h. What is the
relationship between v and h?
2) Conservation of mechanical energy
8
Ballistic Pendulum
In a Ballistic Pendulum a mass m is shot into a
capturing device of mass M with a velocity v.
Masses m and M rise to a height h. What is the
relationship between v and h?