## Sunday, January 3, 2010

### 3-Dynamics Notes

Dynamics

Linear Momentum of an object is the product of its mass and velocity. Linear momentum is in the direction of the velocity.

Principle of Conservation of Linear Momentum - states that the total linear momentum of an isolated system of bodies is constant. (Or the total momentum of a system is constant provided no external net force acts on the system.)

Newton’s First law - a body remains in a state of rest or of uniform motion in a straight line unless a net force acts on it.

Newton’s Second law - the rate of change of momentum of a body is proportional to the external net force acting on it and occurs in the direction of the force.

Force (on an object) - defined as the rate of change of momentum of the object.

Newton’s Third law - when a body A exerts a force on another body B, B exerts a force of the same type that is equal in magnitude and opposite in direction on A.
Impulse (of a force) – the product of the force acting on an object and the time during which the force acts. Note: ( The impulse is equal to the change in momentum of the given object).

Elastic collisions – between two bodies are collisions where the total kinetic energy of the system is conserved. (Here the relative speed of approach is equal to the relative speed of separation.)