Force And Momentum Flashcards
Definition of momentum
Mass x velocity
Unit of momentum
Kgms^-1
Is momentum vector or scalar
It’s vector as it accounts for velocity
Shortened equation for momentum
P=MV
How can Newton’s second law and momentum equate
Both use mass
momentum uses velocity
Acceleration is change of velocity
This can be rewritten
Equation for force from momentum change
F=mv-mu / t or m(v-u) /t =ma
Equation if mass is changing at a constant rate in momentum
F=v Δm /Δt
What is impulse
Force x the time for which the force acts
Equation for impulse
The impulse = Δ(mv)
What makes rebound impacts interesting
You use mv-mu / t but you also have to use + or - signs to denote speed
What is the principle of conservation of momentum
For a system of interacting objects,the total momentum remains constant,provided no external resultant force act on the system
How does conservation of momentum work
In a collision one gains momentum and the other loses momentum which “cancels out” so no momentum is lost
The total final momentum =
The total initial momentum
What is an perfectly elastic collision
A collision where no kinetic energy is lost
What is a perfectly inelastic Collision
A collision where the colliding objects have less kinetic energy after the collision than before the collision
What’s a sign of inelastic collisions
Collision then sticking
What’s a sign of elastic collision
Collision and they bounce off
What is restitution of collision
The number assigned to an object to show the bounciness of the object
How to find constitution of restitution from drop height
h (height after bounce)/H (initial drop height)
How to find constitution of restitution from velocity
v (after collision) / V (before collision)
What happens 2 objects fly apart from rest
They recoil and momentum is equal and opposite
What is recoil
In an explosion where momentum is equal and opposite
