Dynamics Flashcards
What is Newton’s First Law?
A body will remain at constant velocity unless a resultant force acts upon it.
What is Newton’s Second Law?
The rate of change of momentum is directly proportional to the resultant force acting upon it.
What is Newton’s Third Law?
If a body A exerts a force on body B, body B will exert an equal and opposite force on body A.
What is meant by the term Conservation of Momentum?
The vector sum of the momenta of the bodies in an isolated system is constant.
What do all of Newton’s Laws consist of?
velocity, momentum and force
Define momentum.
momentum is a product of mass and velocity.
p = mv
What is the unit for momentum? and what else can be used?
Unit of momentum is kgms^-1
Ns can also be used
What is an inelastic collision?
When kinetic energy is lost to the surroundings.
KE before > KE after
What is an elastic collision?
When no kinetic energy is lost after a collision.
EK before = EK after
What do we need to remember about momenta collisions?
Momentum is a vector quantity and therefore requires a direction. So we need to make either left or right positive or negative.
What 2 things do we need to remember about elastic collisions?
momentum before = momentum after
KE before = KE after
What happens during an explosion problem?
A body splits and the 2 new bodies move in opposite directions from one another.
If the body was stationary before the explosion, then the sum momenta of the 2 parts will be equal to 0.
