Term

Definition
is measure of an objects tendancy to continue on it's present path 


Term
how can the momentum of an object increase 

Definition
increase the velocity, or increase the mass 


Term
what is the equation for momentum and what are it's units 

Definition
p=mv
momentum's units are: kg m/s 


Term
in an isolated system, what is the number one inviolable rule of momentum 

Definition
that momentum is always conserved 


Term
momentum is also a vector, what does this mean in terms of initial momentum and final momentum 

Definition
the initial momentum of the center of mass is equal to the final momentum in both direction and magnitude 


Term
Describe what an elastic collision is 

Definition
When two bodies come into contact with one another, the force generated by the deformed bodies is proportional tothe degree of the deformity. If Hooke's Law is followed, the energy is conserved, and all the energy is transferred back into the motion of the bodies 


Term
Why are elastic equations easy 

Definition
Because the sum of the initial mechanical energies is equal to the final sum of mechanical energies 


Term
what are inelastic collisions 

Definition
These are collisions in which some of the mechanical energy is lost to internal energy 


Term
If any mechanical energy is lost, what type of collision is this 

Definition
This is an inelastic collision 


Term
What is a completely inelastic collision 

Definition
When two objects stick to each other 


Term
What is a reverse collision 

Definition
In a completely inelastic collison, two bodies will stick together and their final momentum equals zero. Therefore, the initial momentum equals zero. To understand a reverse collision mechanism, think of these objects as intially being stuck together and then exploding. The initial momentum is zero, so therefore the final momentum is zero. 


Term
What is the equation for a reverse equation, and give an exmaple of it. 

Definition
A cat is standing on a frictionless board on a frictionless frozen lake, when it jumps to the right, the board must be pushed to the left to conserve energy.
M1V1=M2V2 


Term
When does a partially inelastic collision occur 

Definition
When a object moving at velocity strikes another object that is stationary but of equal mass to the first object. 


Term
The context is: this is a partially inelastic mechanism. Describe how to find the final velocity of the stationary object and the moving object 

Definition
The stationary object will be less than the initial velocity of the moving object, but greater than the initial velocity divided by 2.
The moving object will be greater than zero, but less than the initial velocity divided by 2. 


Term
In a partially inelastic mechanism, is it possible that a moving object could strike a stationary object and bounce backwards 

Definition
Yes. If the stationary object has a large enough mass, it could potentially send that moving object backwards after the collision. 


Term
what is impulse and give its equation 

Definition
The change in momentum, J= delta P 


Term
Context: If a collision approximately follows Hooke's Law, the force during the time of collision is not constant. How can we find the average force from that change in momentum 

Definition
delta MV= F avg * delta t 


Term
Explain how air bags work 

Definition
If the change in time is increased, we know that the average F exerted on a person is decreased. therefore, air bags simply increase the amount of time it takes for the change in momentum to occur, thus lowering the overall force exerted 

