Honors Physics- Momentum and Impulse

Linear Momentum

describes the motion of an object before and after a collision takes place

Inertia

tendency of an object to resist change (Newton’s First Law)

Momentum

• tendency of an object to stay in motion

• momentum= inertia in motion (js to kinda think about it)

• vector (magnitude and direction needed)

SI Unit for Momentum

kgm/s

Variable for Momentum

p (lowercase P)

Momentum and Velocity Relations

• no velocity= no momentum

• object increases velocity= momentum increases (vice versa)

• momentum is directly proportional to the velocity

• the less momentum there is, the easier it is to stop

Force and Momentum Relation

Force is change in momentum over a change in time

Impulse

• for a constant external force, the product of the force and the time over which it acts on an object

• large force= objects momentum changes in short time

• smaller force will take a much longer time to cause the same change in momentum

Impulse-Therom “Idea”

larger mass objects have larger momentums therefore they are harder to stop

SI Unit for Impulse

• N*s

• kgm/s

Variable for Impulse (idk if we learned this)

J

Law of Conservation of Momentum

total momentum of all objects interacting with one another remains constant regardless of the nature of the forces between objects

Is momentum always conserved in a collision? If not, where is it not conserved?

yes, it is always conserved.

Is kinetic energy always conserved in collisions? If not, where is it not conserved?

No. It is not conserved in inelastic and perfectly inelastic collisions.

Perfectly Elastic Collision

• object that maintains their original shape through the collision

• no kinetic energy lost

• objects DO NOT stick together

• Ex. subatomic particles

Elastic Collision

• objects are deformed during the collision, but maintain their original shape after colliding

• no kinetic energy lost (Kinetic energy remains constant!!)

• Ex. kicking a soccer ball

Inelastic Collision

• objects are deformed during the collision

• loses Kinetic Energy

• bounces off each other

• Example: car accident

Perfectly Inelastic Collisions

• objects join together after a collision to form one mass

• loses kinetic energy

• Ex. bullet being shot into a piece of wood and getting stuck in there

SI Unit for Force

N (netwons aka kg*m/s²)

SI Unit for Time

seconds

SI Unit for Distance

meters

Variable for Force

F

Variable for Time

t

Variable for Distance

d