newtons laws and momentum

What are Newton’s 3 laws of motion

1. A body continues in its state of rest or uniform motion unless acted on by a resultant force

2. The rate of change of momentum of a body is proportional to the applied force and takes place in the direction of the force

3. For every action, there is an equal and opposite reaction.

See photo for equations

What does it mean if a resultant force on a body = 0

This deals w Newton’s first law

Tell us that one of the following is true

• the body is at rest, or

• the body is moving at a constant velocity

Linear momentum

Linear momentum of a body is the product of its mass and its velocity

Equation for momentum

momentum = mass x velocity

Unit for momentum

kg m s^-1

OR

N s

Is momentum a scalar of vector

vector

Law of conservation of linear momentum

In the absence of external forces, the total momentum of a system of bodies is constant

Elastic Collisions

When two objects collide and bounce apart. Both the momentum and kinetic energy are conserved (almost no energy is lost to heat, sound or deformation)

Inelastic collisions

When two or more objects collide, stick together, and move off together in one direction

Momentum is conserved but kinetic energy is not (friction)