newtonslaws

 Sir Isaac Newton

 Newton's 1st Law: An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force Newton's 2nd Law:  Newton's 2nd law describes the relationship between an object's mass and the force it takes to change its motion (acceleration). The acceleration is directly proportional to the net force.

An object will only accelerate if there is a [|net] or [|unbalanced force] acting upon it. The presence of an unbalanced force will accelerate an object - changing either its speed, its direction, or both its speed and direction.

The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.  Force = Mass x Acceleration F = m x a The definition of the standard metric unit of force is stated by the above equation. One Newton is defined as the amount of force required to give a 1-kg mass an acceleration of 1 m/s/s.

Newton's 3rd Law: For every action, there is an equal and opposite reaction. The size of the forces on the first object __equals__ the size of the force on the second object. The direction of the force on the first object is __opposite__ to the direction of the force on the second object.

Some forces result from //contact interactions// (normal, frictional, tensional, and applied forces are examples of contact forces) and other forces are the result of action-at-a-distance interactions (gravitational, electrical, and magnetic forces)

[|BBC: History of Sir Isaac Newton] [|The Physics Classroom Tutorial (glenbrook K-12)]