Physics Chapter 5:
Momentum and Collisions
Learning targets:
forces acting in a system
~2. I can diagram and calculate the components
of force and motion
~3. I can calculate and compare the physical property
of momentum between two objects
~4. I can explain the idea of impulse as it reacts
to change in momentum
~5. I can apply the law of conservation to momentum
Vocabulary:
Momentum~ mass in motion
Impulse ~ change in momentum
Conservation ~ closed system no change
Elastic~ bounce and spring g back into motion
Inelastic ~ objects that collide and stick together and objects are deformed
Formula's
Formula's
∆p=F∆t=∆p=m∆v
Elastic collisions:
m1v1+m2v2=m1v1+m2v2
Inelastic collisions:
m1v1+m2v2=(m1+m2) v
•p=momentum (kg*m/s)
•m=mass (kilograms)
•v=velocity (m/s)
•∆p=impulse (newtons-seconds)
Key concepts
Newton's Third Law:
~Forces
- A force is a push or pull that acts upon an object as a result of interaction with other objects
- Contact interactions are normal, frictional, tensional and applied forces
~"For Every Action, There is an Equal but Opposite Reaction"
- In every interaction, there are a pair of forces acting on two interacting objects
- The size of the force on the initial object equals the force on the second object
- The direction of the force of the first and second object are opposite of each other
- Forces always come in equal and opposite action and reaction force pairs
Momentum:
~ Momentum
- Mass in motion
- A quantity describing an objects resistance to stopping
- If an object is in motion, it has momentum
- The amount of momentum an object has depends on how much stuff is moving and how fast it's moving
- Impulse is change in momentum
- Impulse momentum Theorem:
- Large force and small time
- Small force and long time
- Collisions: momentum is conserved, therefore before=after, supporting The Law of Conservation of Momentum
- closed systems: no changes in mass
- Isolated systems: When an external force on a closed system is equal to zero (no applied force from outside)
- No system is truly isolated on earth, so we assume ideal
- Types of Collisions:
- Assume perfect or ideal
- Inelastic- objects collide together and stick, deforming
Ex: Clay being thrown on the ground
- Elastic- objects bounce and spring back into their shape
Ex: Bumper Cars