Transcript Unit One: Speed, Velocity, Acceleration, & Force

Speed, Velocity, Acceleration,
& Force
Motion: The change in position of an object
Reference Point: a place or object used for
comparison to determine if something is in motion.
(also called frame of reference)
An object is in motion if it changes
position relative to a reference point.
Speed: The distance an object travels in one unit of time.
Average Speed (average velocity): v = d ÷ t
(v = velocity, d = distance, t = time)
Example: an object rolls 2 meters in 4 seconds.
2 ÷ 4 = 0.5 m/s
To solve for missing factor
when the other 2 are known:
t = d ÷ v or
d = v∙t
Velocity: Speed in a given direction
(example: 10 km/hr north)
Graph: a picture of the data used to
assist in data analysis
Acceleration: The rate at
which velocity changes
{change in speed
and/or direction}
Acceleration: a = vf – vi
t
(a = acceleration, vf = final velocity,
vi = initial velocity, t = time)
Ex: an objects initial velocity is 2 m/s
but increases to 4 m/s second after 5 seconds
4 m/s – 2m/s = 2 m/s
5s
5s
0.4 m/s2
Δ (delta) is a symbol that means change in.
To solve for missing factors when the
other 2 are known: a = Δv÷t
Δv =a∙t
t = a∙ Δv
Force: A push or pull exerted on an object
Newton (N): A unit of measure for force.
1 N = the force required to accelerate 1 kg of mass at 1 m/s2
Balanced Forces: Equal forces acting on an object in
opposite directions (no change in motion)
Unbalanced Forces:
A nonzero net force, which
changes an object’s motion.
Net Force: The overall force
on an object when all individual
forces acting on an object are
added together.
The 4 Fundamental Forces:
1. Gravity: The force that pulls
objects toward each other
(more detail in later units)
2. Nuclear Forces
Strong Force: force in the nucleus
that causes protons and neutrons
to be attracted to each other.
Weak Force (electrical force) is a
long range force and causes
repulsion of protons far apart.
It is responsible for the decay of
isotopes (more in chemistry).
3. Electromagnetic force
(more detail in later units)
4. Dark Energy : believed to be the
cause of universal expansion
(space science)
4 forces video clip