# Force & Motion - Moody High School

Mechanics

Nov 14, 2013 (4 years and 7 months ago)

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Motion occurs when an object changes
position

Relative motion

motion that is not obvious

If sitting in desk, not moving relative to the desk
or school; but are moving relative to the other
planets & Sun

Unbalanced forces cause changes in motion

Relative to frame of reference

DISTANCE

How far something has
traveled

Scalar Quantity

described
by magnitude (numerical
value); 10m

Distance standard unit = m

DISPLACEMENT

Distance & direction of an
object’s change in position
from the starting point

Vector Quantity

both
magnitude & direction; 10
m, East

4m X 2m

Distance?

Displacement?

SPEED

How long it takes to go a
certain distance

Standard Unit

m/s

On a graph, slope is equal
to speed

Speed (velocity) =

distance / time

v=d/t

ACCELERATION

How long it takes to go
from being at 1 speed to
another

Standard Unit

m/s
2

Acceleration = final velocity

Initial Velocity/time

a =
v
f

v
i
/time

SPEED

Distance and object travels
per unit of time

Speed = distance/time

VELOCITY

Speed & direction of a
moving object

S = d/t or V= d/t

Standard Unit

m/s

Speed = distance/time

Product of an object’s mass & velocity

Momentum = Mass x Velocity or p = m x v

Standard units

kg x m/s

Mass & velocity together represent the force
needed to stop an object in motion

Force is needed to start & stop an object’s motion

Work is the transfer of energy when applied
force makes an object move in the direction
of the applied force

Formula

work = force x distance

Standard units

Work = joule (J)

Force = Newton (N)

Distance =
meter (m)

Power is the amount of work done in a certain
amount of time

Formula

Power = work/time or P = W/t

Standard units

Power = Watt (W)

Time = Second

An object will remain at rest, or continue to
move at a constant velocity (speed) unless a
net force acts on it

Net force on an object is equal to its mass
times its acceleration

For every force acting on an object, the
object will exert an equal, yet opposite, force

For every action there is an equal & opposite
reaction

ie
. rocket