3.1 Forces / 3.2 Newtons First Law of Motion

from note 3.1 /3.2 with the following glossary terms: Dynamics, Newton (N), System diagram, Free-body diagram, Applied force, Tension, Normal force, Friction, Force of gravity, Net force, Four fundamental forces including range, strength and effect, Inertia, First law of motion

Dynamics

The study of the causes of motion

Newton (N)

the unit of force

1 N = 1 kg x m/s ²

System diagram

a simple sketch of all objects involved in a situation. Helps out determine which objects push or pull on other objects

Free-body diagram

a drawing of an object showing all the forces that are acting on it.

The object is shown as a dot, with arrows originating from the dot labeled with which force is being used.

Applied force

F_A

a force that results when one object IS IN CONTACT with another and pushes or pulls on it.

Tension

F_T

a pulling force from a ROPE OR STRING on an object that always points toward the rope or string

Normal force

F_N

a PERPENDICULAR FORCE exerted by a surface on an object IN CONTACT with the surface

always points away from the surface

Friction

F_f

OPPOSES the sliding of 2 surfaces across one another

always PARALLEL to the surface and acts opposite to the objects motion or ATTEMPTED motion

Force of gravity

F_g

Force of attraction between any two objects due to their mass

Non-contact or action at a distance force

Net force

F_net

the SUM of all forces acting on an object e.g:

F_y = 102 N [up] + 102 N [down] = 0 N (are equal, sum is 0)

F_x = 83 N [W] + 35 N [E] = 48 N [W] (flip direction to get sum)

Four Fundamental forces

4) -

Type of Force	Range	Description
Gravitational force	(infinite range)	Force of attraction between all objects in the universe
Electromagnetic force	(infinite range)	Force caused by electric charges. holds atoms and molecules together
Strong Nuclear force	(less than 10-15 m range)	Force that holds All the protons and neutrons together in the nucleus of an atom.
Weak Nuclear force	(less than 10-18 m range)	the Force responsible for interactions involving elementary particles. in some nuclear reactions neutrons and protons can transform into other particles (try to stabilize the unbalanced nucleus to make stable)

Strength and Effect

Type of Force	Strength	Effect
Gravitational	1	attract only
Electromagnetic	1020	attract and repel
Strong Nuclear	1038	attract and repel
Weak Nuclear	1025	attract and repel

Inertia

the property of matter that causes it to resist change in motion

Inertia is directly proportional to the mass of the object

First law of motion

an object will remain at rest or continue to move at constant velocity when the net force on the object is ZERO