Download Copy of Motion Notes

SOL: PS.10!
I.  Measuring Motion
A. Distance – how far an object has
moved
1. Common unitsà m, cm, km
2. Formula à speed x time
3. Displacementà distance and
direction; ex. 25 km, North
*** Distance or Displacement?
a. 45 m à distance
b. 2 cm, left àdisplacement
c. 60 km, West à displacement
d. 100 cm à distance
B. Speed- how far an object travels in a
certain amount of time
1. Common unitsà m/s, km/h
2. Formula à distance/time
3. Velocity à speed and direction
Ex. 55 km/h, East
** Speed or Velocity?
a. 20 m/s àspeed
b. 70 km/h, West àvelocity
c. 5 m/s àspeed
d. 9.8 m/s, down àvelocity
C. Time- refers to how long an object
takes to travel a distance
1. Common unitsà seconds, hours
2. Formula à distance/speed
*Quick Calculations
Practice Problems
1.  A car travels 1000 meters in 20 seconds.
What is its speed?
s = 50 m/s
2. An airplane travels at 240 km/hr for 2
hours. What distance is traveled?
d = 480 km
3. A taxi cab travels 140 km at a rate of
70km/hr. How long does the trip take?
t = 2 hr
D. Acceleration- change in velocity
1. Common unitsà km/h/s, m/s2
2. Formulaà (final speed-starting speed)
time
3. Positive acceleration- speed is
increasing
4. Negative acceleration- speed is
decreasing
** also known as deceleration
Practice Problems for Acceleration
Final speed - starting speed
time
1. A car accelerates from rest to 30m/s in
15 seconds. What is its acceleration?
a = 2 m/s2
2.  A car decelerates from 80m/s to 40 m/s
in 2 seconds. What is its acceleration?
a = -20 m/s2
II.  Nature of Forces
A. Force - a push or pull on an object
1. Can cause an object’s motion to
change
2. Unitsà Newtons (N) or kg x m/s2
3. Net force àsum of forces
a. Balanced force- same size,
opposite directions; no movement
b. Unbalanced force- different
size, same/different direction;
movement occurs
B. Newton’s 1st law of motion
1. Also called the law of inertia
2. Law states- an object at rest
remains still and an object in
motion keeps moving unless an
outside force changes it
*Examples
a. Pulling off a tablecloth
leaving dishes behind
b. Leaning forward when the
car comes to a stop
C. Newton’s 2nd Law
1. Shows the relationship between
force, mass, and acceleration
* The greater the force the greater the
acceleration
* Acceleration and mass change opposite of
each other
2. Formulaà F = mass X acceleration
3. Measurement tool à spring scale
F
mxa
F
mxa
Practice Problems for Force
F= ma
m = F/a
a = F/m
1.  What force is needed to push your 80 kg
friend on a sled at an acceleration of 0.5 m/s2?
F = 40 N
2.  A student pedaling a bicycle applies a net force
of 200N. The mass of the rider and the bicycle
is 50kg. What is the acceleration of the bike
and rider?
a = 4 m/s2
D. Newton’s 3rd Law
1. Statesà For every action there
is an equal and opposite
reaction
2. Exampleà a rocket fires its
engines downward and the
rocket goes upward
Review of Newton’s Laws of Motion
1. A magician pulls a tablecloth out from
under dishes and glasses on a table without
disturbing them.
Answer: 1st law
2. A person’s body is thrown outward as a
car rounds a curve on a highway.
Answer: 1st law
Review of Newton’s Laws of Motion
3. Rockets are launched into space using jet
propulsion where exhaust accelerates out
from the rocket and the rocket accelerates
in an opposite direction.
Answer: 3rd law
4. A picture is hanging on a wall and does not
move.
Answer: 1st law
Review of Newton’s Laws of Motion
5. A person not wearing a seatbelt flies
through a car window when someone slams on
the breaks because the person’s body wants
to remain in continuous motion even when the
car stops.
Answer: 1st law
6. Pushing a child on a swing is easier than
pushing an adult on the same swing, because
the adult has more mass.
Answer: 2nd law
Review of Newton’s Laws of Motion
7. A soccer ball accelerates more than a
bowling ball when thrown with the same
force.
Answer: 2nd law
8. A soccer player kicks a ball with their foot
and their toes are left stinging.
Answer: 3rd law
Review of Newton’s Laws of Motion
9. A student leaves a pencil on a desk and the
pencil stays in the same spot until another
student picks it up.
Answer: 1st law
10. Two students are in a baseball game. The
first student hits a ball very hard and it has
a greater acceleration than the second
student who bunts the ball lightly.
Answer: 2nd law
III.  Friction and Gravity
A. Friction – force of resistance
between objects that touch
B. Types of Friction
1. Sliding- objects slide past each
other; ex. hockey puck on ice
2. Rolling- objects roll over another;
ex. bowling ball going down the lane
3. Fluid- caused by gases or liquids;
ex. Baseball flying through
the air
C. Projectile motion - objects
travel in curved paths due to
gravity and inertia
D. Centripetal force - keeps
objects moving in a circle; ex.
Amusement park rides,
satellites, and spinning a
bucket of water
without spilling it
E. Law of gravitation - a force of
attraction exists between objects
1. Gravity gives the universe structure
2. Weight – the force of gravity on an
object
3. Acceleration due to gravity- 9.8m/s2
**All objects fall with the same
acceleration regardless of mass
** Air resistance determines how fast
something falls, not gravity
IV. Graphing Motion
Highlight the key terms associated with
each graph shape.
A. Constant
B. No
C. Average
IV. Graphing Motion
Highlight the key terms associated with
each graph shape.
D. Constant
E. No
IV. Graphing Motion
Highlight the key terms associated with
each graph shape.
F. Average
G. Negative