Momentum Concepts [Checking my Understanding]

UNDERSTAND THE CONCEPTSIn summary, elastic collisions involve objects bouncing off of each other and conserving kinetic energy, while inelastic collisions involve the transformation of kinetic energy into other forms and may result in objects sticking together. Explosions are a form of inelastic collisions, as kinetic energy is not conserved. Momentum is always conserved in all collisions, and to determine if a collision is elastic or inelastic, one must compare the kinetic energy before and after the collision. To solve problems involving elastic collisions, one must consider the total momentum and kinetic energy before and after the collision, while for inelastic collisions, one must also consider the fact that the objects stick together and share a common velocity after the collision.
  • #1
WolfishGrin
4
0

Homework Statement


What are elastic and inelastic collisions? What is an explosion?

Homework Equations


N/A

The Attempt at a Solution


In elastic collisions, the colliding objects bounce off of each other to some degree, and kinetic energy is conserved. Inelastic collisions involve the transformation of some initial kinetic energy into other forms, such as heat or potential energy. Objects that collide in a completely inelastic way stick together. Explosions are a form of inelastic collisions, for kinetic energy is not conserved.

How can I elaborate upon this? I'm still slightly confused about momentum in general, and I don't understand explosions whatsoever. My notes state that kinetic energy is conserved for explosions, but other online sources state the opposite. That's never a good thing.
 
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  • #2
What specifically about momentum are you confused about? Momentum is the product of mass and velocity, and is conserved in all collisions.

Do you think that kinetic energy is conserved in an explosion? Think about it; what actually happens in an explosion?
 
  • #3
According to Newton's 3rd law, the forsces exert on each other are always equal in magnitude and opposite in direction. thus we define the total momentum of a system between two blocks of masses m1,m2 and v1,v2 as momentum=mv1+mv2
hence we arrive at the conservation of momentum,this states when no resultant force acts upon a system of bodies, and the total momentum of the stystem remains unchanges
total momentum before= total momentum after

elastic collisions are when the interaction forces between two bodies are conserved, the Ek of the system is the same after the collison as before the collison. therefore Ek is conserved

Inelastic collisions is a collision in which the total Ek of the system after the collision is less than the Ek before the collision. in one kind of inelastic collision, the colliding bodies stick together and move as one unit after the collison.


To determine wheather or not a collision is elastic or inelastic find the Ek before and the Ek after.If it is not conserved it is inelastic if it is it is elastic

Problem solving stategy for elastic collison
a) find the total momentum/Ek before collison
b)find the total momentum/Ek after
c) remember to consider a) = b) in problem solving

problem solving strategy for inelastic collision
Consider two masses Ma and Mb right before a collison then
a)find the total momentum before collision
i) MaVa1+MbVb1
b) find the total momentum after the collision
ii)(Ma+Mb)V2
c) remember to consider a) = b)
iii) remember they stick together in an inelastic collision for part b) and a) not equal to b), in the case of their kinetic energies

if the masses and velocities are known then we can compute the final velocity. suppose we have a body of mass Ma and initial velocity V1 and it collides inelastically with a body of mass Mb initially at rest

INITIALLY
(MaV1+Mb*o)
FINALLY
(Ma+Mb)V2
*After the collision the two bodies have a common velocity V2

HOPE THIS HELPS YOU
 

1. What is momentum?

Momentum is a physics concept that refers to the quantity of motion an object has. It is calculated by multiplying an object's mass by its velocity.

2. How is momentum different from velocity?

Momentum takes into account both an object's mass and its velocity, while velocity only considers the speed and direction of an object's motion.

3. What is the equation for calculating momentum?

The equation for calculating momentum is p = mv, where p is momentum, m is mass, and v is velocity.

4. What are the units of momentum?

The units of momentum are kilogram-meters per second (kg*m/s).

5. How does momentum relate to Newton's Laws of Motion?

According to Newton's Second Law of Motion, the force acting on an object is equal to its mass multiplied by its acceleration. This can also be written as F = ma. Momentum is closely related to force, as an object's momentum will change if a force is applied to it. This relationship is expressed as F = dp/dt, where F is force, p is momentum, and t is time.

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