21 terms

# Forces and Vectors

#### Terms in this set (...)

Force
A push or a pull.
Gravitational Force
An attractive force between all objects
Electromagnetic Force
Forces between particles as a result of electric and magnetic attraction
Strong Nuclear Force
Holds particles in atomic nucleus together
Vector
Represented by an arrow
Arrow length: Magnitude

The vectors to the right are considered positive, and to the left are considered negaitve

Velocity, acceleration, and force can all be represented by this arrow
Newton's First Law
An object with no net force acting on it remains at rest or moves with constant velocity in a straight line (once set in motion)

If there is a net force, an unbalanced force exists
If there is not net force, there is not unbalanced force
Inertia
An object in motion remains in motion and an object at rest remains at rest unless there is an outside force acting on it.

The greater the mass, the greater the inertia
Newton's Second Law
The acceleration of a body is directly proportional to the net force on it, and inversely proportional to its mass.

Fnet=ma
a=Fnet/m

No acceleration=no net force
Acceleration
The same direction as the force acting on it
Newton's Third Law
When one object exerts a force on a second object, the second object exerts a force on the first that is equal in magnitude but opposite in direction.

The two forces are action-reaction pairs
Mass
Amount of matter that an object contains

Scalar (g or kg)

Gravitational: m=w/g
Inertial: m=Fnet/a

Mass never changes depending on location
Weight
Mass x Gravitational Acceleration

vector (N)

w=mg
g=9.8 m/s^2

Weight can change depending on location
Vector Quantity
requires magnitude and direction

force, velocity, acceleration, displacement, position, weight
Scalar Quantity
magnitude only

mass, volume, speed, distance
same direction=zero degrees (maximum result)
opposite direction=180 degrees (minimum result)

Fnet = F1x + F2x + F3x ...
Fnet = F1y + F2y + F3y ...
Parallelogram Method

Arrow Tail to Arrow Head Method
Free Body Diagram
A diagram that shows the forces acting on the object
0 degrees = same direction ; maximum result
180 degrees = opposite direction ; minimum result
90 degrees = perpendicular directions
parallelogram
analytically

R^2 = Rx^2 + Ry^2
theta = arctan (Ry/Rx)

CALCULATOR MUST BE IN DEGREE MODE!
Equilibrium
When there is no net force and no acceleration
Equilibrant Force
Equal magnitude and opposite direction of net force
Frictional Force
Opposes motion between two surfaces in contact. It is parallel and opposite to the direction of motion

Static=opposes start of motion
Sliding=opposes surfaces that are already moving

STATIC IS GREATER!