Forces

> > IdentifyIdentify the law that says the law that says that objects change their that objects change their motion only when a net force is motion only when a net force is applied.applied.

> > Relate Relate the first law of motion the first law of motion to important applications, such to important applications, such as seat belt safety issues.as seat belt safety issues.

> > CalculateCalculate force, mass, and force, mass, and acceleration by using Newton’s acceleration by using Newton’s second law.second law.

Sir Isaac NewtonBritish scientist (1642-1727)

ForceGravityCalculus

http://www.youtube.com/watch?v=iH48Lc7wq0U

Newtons Law's Clip

He formed 3 laws to show the relationship between motion and force.Motion- change in positionForce- a push or pull that affects motion of an object

An Object at rest remains at rest and an object in motion maintains its velocity unless acted upon by an unbalanced force.

An unbalanced force must be greater than zero

Inertia (def)- the tendency of an object to resist change in its velocity or lack of

Inertia Clip

The ability of matter to resist a change in motion is dependent on its mass.

Larger masses are harder to change than smaller

Example- playing Example- playing softball with a bowling softball with a bowling ballball

Seatbelts Seatbelts provide provide protection protection against a against a persons persons own inertia.own inertia.

The unbalanced force acting on an object equals the objects mass times its acceleration

Force= mass X acceleration F=m x a

Mass- amount of matter in an object

Acceleration- any change in velocity ex.

Empty vs full cart.

Size of force and mass effect acceleration.

SI units for force is NEWTON- a derived unit (2 units put together)

kg x m/s2 mass (kg)and acceleration (m/s2)

F= (m * a) a= F/m