What is the definition of momentum?
Momentum ($\vec{p}$) is a measure of how much "oomph" an object has in motion. It's the product of an object's mass ($m$) and its velocity ($\vec{v}$).
What is the definition of impulse?
Change in momentum ($\Delta \vec{p}$), also known as impulse ($\vec{J}$), is the result of a force acting over a period of time. It's the difference between the final and initial momentum.
What is the Impulse-Momentum Theorem?
Impulse is equal to the change in momentum. It's also equal to the force ($\vec{F}$) multiplied by the time interval ($\Delta t$) over which the force acts: $\vec{J} = \Delta \vec{p} = \vec{F}\Delta t $
What is the law of conservation of momentum?
In a closed system (no external forces), the total momentum remains constant. This means the total momentum before a collision equals the total momentum after the collision: $\vec{p}_{initial} = \vec{p}_{final}$
Define an elastic collision.
A collision in which kinetic energy is conserved. Objects bounce off each other without losing energy (idealized).
Define an inelastic collision.
A collision in which kinetic energy is not conserved. Some energy is lost as heat, sound, or deformation. Objects may stick together (perfectly inelastic).
What is the effect of a larger force acting over a longer time interval on momentum?
A larger change in momentum.
What happens when multiple forces act on a system?
The net force (vector sum of all forces) determines the change in momentum.
What happens when an object is at rest?
Its initial momentum is zero.
What happens when objects stick together after a collision?
You'll use the combined mass when calculating the final velocity of the system.
What is the effect of increasing the time of impact (e.g., with an airbag)?
It reduces the force on the object.
What are the differences between elastic and inelastic collisions?
Elastic: Kinetic energy conserved, objects bounce. | Inelastic: Kinetic energy not conserved, energy lost as heat/sound, objects may stick.
