Name _______________________________________ Homeroom __________
Date ___________
Use these notes to study from as we begin our
unit on Motion
by Liz LaRosa
www.middleschoolscience.com
Motion: a change in
position, measured by distance and time.
Frame of reference: the point from which movement is
determined.
- To measure movement, some point must be considered as nonmoving.
- Earth is the most common frame of reference, however:
Speed: the distance traveled by a moving object per
unit of time.
- To calculate speed, use the equation - Speed = distance / time
- Speed only gives distance and time.
Average speed: the speed of moving objects is not
always constant:
- Average speed = total distance / total time
Velocity: speed in a given direction.
- Velocity gives distance, time, and the direction of travel.
Acceleration: The rate of change in
velocity.
- To calculate acceleration, use the equation:
Acceleration = (Final Velocity) - (Original Velocity) / Time
Deceleration:
- A term commonly used to mean a decrease in speed.
Force: any push or pull.
- Forces give energy to objects.
- Forces cause a change in motion.
Friction: a force that opposes motion.
Gravity: the force of attraction between all
objects in the universe.
- Gravity is the weakest of the known natural forces, only becoming obvious
when massive objects like stars and planets are involved.
Free fall - an object falling under the
influence of gravity.
- Near the surface of the earth all objects are accelerated by gravity at a
rate of 9.8 m/s/s
Weight: the effect of gravity on an objects mass
Momentum: the product of the
mass of an object and its velocity.
- All moving objects have momentum.
- To calculate momentum, use the equation:
Momentum = Mass x Velocity
The Three Laws of Motion by Sir Isaac Newton explain all
aspects of motion.
- Newton's First Law describes motion produced by balanced forces.
- An object at rest will remain at rest, and a moving object will remain
at a constant velocity unless unbalanced forces act on it.
Newton was first to use the term inertia to describe the
tendency of objects to remain in motion or stay at rest. Inertia comes from
the Latin word iners, which means "lazy".
- Newton's Second Law describes motion produced by unbalanced forces.
- This law is best stated using the equation:
Force = mass X acceleration
- Acceleration is always in the direction of the unbalanced force.
- The units of force are "Newtons".
- 1 N = 1 kg X 1 m/s/s
- Newton's Third Law explains why forces act in pairs.
- For every action, there is an equal and opposite reaction.
- Forces always act in pairs.
Note:
Notes have been taken from the following source: Physical Science Class
http://pc65.frontier.osrhe.edu/hs/science/hps3.htm
