Unit 6: Bell Ringer.
If you are sitting still in your seat on a bus
that is traveling 100 km/h on a highway, is
your body at rest or in motion? Explain.
Unit 6: Force and Motion.
Sir Isaac Newton (1643-1727)
Although he did not
discover all three laws
of motion, he explained
them in a way that
helped many people
understand them.
Unit 6: Force and Motion.
Newton’s First Law of Motion
“An object at rest
remains at rest and an
object in motion
remains in motion at
constant speed and in
a straight line unless
acted on by an
unbalanced force.”
Unit 6: Force and Motion.
What is force?!
Force is simply a push or pull.
Forces have SIZE AND DIRECTION
Unit 6: Force and Motion.
The unit for force: Newton (N)
BrinPop on Force: https://www.brainpop.com/science/motionsforcesandtime/force/
Unit 6: Force and Motion.
What does this mean?
Basically, an object will “keep doing
what it was doing” unless acted on by
an unbalanced force.
If the object was sitting still, it will
remain stationary.
If it was moving at a constant
velocity, it will keep moving.
Unit 6: Force and Motion.
Newton’s First Law is also called
the Law of Inertia
Inertia: the tendency of an object to
resist changes in its motion
Unit 6: Force and Motion.
An object with a small mass has less
inertia than an object with a large mass.
This means… it is easier to start and change the motion
of an object with a small mass!
Unit 6: Force and Motion.
Real Life Inertia Examples
Inertia makes it easier to push the lawn mower than it
does to start pushing a car!
Unit 6: Force and Motion.
Momentum: property of a moving object
that depends on the mass and velocity.
The more momentum, the harder it is to stop or
change the direction of the object!
Unit 6: Force and Motion.
But wait…
If objects in motion tend to stay in motion,
why don’t moving objects keep moving forever?
Unit 6: Force and Motion.
Friction: is a force that oppose motion
between two surfaces that are touching
Example: A book sliding across a
table slows down and stops because
of the force of friction.
Friction song!! https://www.youtube.com/watch?v=U5f7SyvHUac
Unit 6: Force and Motion.
In outer space, away from gravity and any
sources of friction, a rocket ship launched
with a certain speed and direction would
keep going in that same direction and at that
same speed forever.
Unit 6: Force and Motion.
Pushing a solid
over a solid.
Unit 6: Force and Motion.
Wheels reduce
friction so things are
easier to move.
Unit 6: Force and Motion.
The force between solids and a liquid or gas.
Unit 6: Force and Motion.
This force balances others so the
object does not move
Unit 6: Force and Motion.
How to reduce friction
Unit 6: Force and Motion.
Inertia Ball LAB
1. Work on Newton's Laws vocabulary.
Study. Go over notes. Read through lab/ try to answer any
that you can.
Read through textbook pg 145-147.
2. Perform lab when sent into the hall. (5-10 minutes)
3. Answer lab questions with group.
HAND IN ONE LAB FOR THE group (SUMMATIVE)!
4. When done, start homework. (20 point SOL Menu)
Unit 6: Force and Motion.
Bell Ringer:
1. This crash dummy is NOT wearing a seat belt. Explain, using
Newton’s first law of motion, what will happen if he were to
get into a collision. (think about momentum and inertia)
Unit 6: Force and Motion.
Newton’s Second Law of Motion
“The acceleration of an object depends on
the mass of the object and the amount of
force applied.”
Unit 6: Force and Motion.
What does that mean?... Let’s look at the law on 2 parts…
1) Acceleration depends on mass!
If given the same force
Less mass -> greater acceleration
Greater mass -> less acceleration
Unit 6: Force and Motion.
2) Acceleration depends on force!
If given the same mass
Less force-> less acceleration
Greater force -> greater acceleration
Unit 6: Force and Motion.
How to express Newton’s second law
mathematically
F = ma
Unit 6: Force and Motion.
https://www.youtube.com/watch?v=dQmYBF_Sd8I
Unit 6: Force and Motion.
Let’s try:
A little boy pushes a wagon with his dog in it. The
mass of the dog and the wagon together is 45 kg.
The wagon accelerates at 0.85 m/s2. What force
is the boy pulling with?
Unit 6: Force and Motion.
Now your turn… try the rest of the question on the
“Newton’s Second Law of Motion- Worksheet”
Unit 6: Force and Motion.
Suppose you drop a large rock and a small
rock at the same time from the same height.
Which do you think will land first?
Gravity BrainPop: https://www.brainpop.com/science/motionsforcesandtime/gravity/
Misconcceptions: https://www.youtube.com/watch?v=_mCC-68LyZM
Unit 6: Force and Motion.
All objects accelerate towards the ground at
the SAME rate.
2
9.8 m/s =
acceleration due
to gravity
Unit 6: Force and Motion.
Show in class vacuum tub demo
Unit 6: Force and Motion.
On Earth, falling objects will be slowed down
by air resistance.
(fluid friction between the falling object and the air)
https://www.youtube.com/watch?v=-cCt9JobjOg
Unit 6: Force and Motion.
You may watch any of the following BrainPop videos:
Play Gizmo games…
1.
2.
3.
4.
5.
6.
Go to Google. Click on the first link after searching GIZMO.
Click on Enroll in a Class
Enter the Class code: XYWWEWVCYR
Click on “I need to create an ExploreLearning Account”
Type in your first name, last initial, create a user name, and password
Play with Gizmos on forces! Try answering the questions that are underneath
each game as you go! 
OR work on SOL menu project due NEXT CLASS
Unit 6: Force and Motion.
HAND IN SOL MENU PROJECT
Bell Ringer:
1. The whale shark is the largest of all fish and can have the
mass of three adult elephants. Suppose that a crane is lifting
a whale shark into a tank for delivery to an aquarium. The
crane must exert an unbalanced force of 2500 N to lift the
shark from rest. If the shark’s acceleration equals 1.25 m/s2,
what is the shark’s mass?
Unit 6: Force and Motion.
Newton’s Third Law of Motion
“Whenever one object exerts a force on a
second object, the second object exerts an
equal and opposite force on the first.”
Unit 6: Force and Motion.
All forces act in pairs
Unit 6: Force and Motion.
What are some examples of
action and reaction force
pairs?
Unit 6: Force and Motion.
Time for Rocket Balloon Lab!!
ALL lab group members needs to turn in COMPLETED lab
COMPLETE the next handouts “Newton’s Third Law” & “Newton’s Graphic
Organizer”… do not turn these in! (we will go over it)
If you have COMPLETED everything above, YOU MAY:
• Watch BrainPop videos on Force and Motion
• Do your HW: JLab FIXED SET 4
• Read through textbook pages 150-151
Unit 6: Force and Motion.
Law of Universal Gravitation: all objects in the
universe attract each other through gravitational
forces; the size of the force depends on the masses
of the objects and the distance between them.
Unit 6: Force and Motion.
• Gravitational force is small between objects with small
masses.
• Gravitational force is large between objects with larger
masses.
• If the distance between two objects is increased, the
gravitational force pulling them together is reduced
Unit 6: Force and Motion.
Bell Ringer: What did we learn from
the rocket balloon lab last class?
Unit 6: Force and Motion.
DONE WITH THE QUIZ?: Please take out the 2
sheets from last class, and be working on
those, we will be going over them!
Unit 6: Force and Motion. Work and Power.
Work
Occurs when a force
causes an object to
move in the direction
of the force.
Work only occurs when
there is movement in
the same direction as
the force!
Unit 6: Force and Motion. Work and Power.
Work or
no work?
Unit 6: Force and Motion. Work and Power.
Calculating Work
W=F×d
Work = Force × distance
SI Units of
Measurement
Work = joules (J)
Force = Newtons (N)
d = meters (m)
Unit 6: Force and Motion.
Work increases when the amount of
force OR distance moved increases
Work = Force × distance
Unit 6: Force and Motion. Work and Power.
Power
The rate at which work is done.
(Power is how fast the work happens!)
Unit 6: Force and Motion. Work and Power.
Calculating Power
P=W÷t
Power = Work ÷ time
SI Units of
Measurement
Power = watt (W)
Work = joules (J)
t = seconds (s)
Unit 6: Force and Motion.
Power increases when the time it takes
to do work decreases
Power = Work ÷ time
Unit 6: Force and Motion.
Brick on a Stick Lab
EACH person hands in a lab
When you are done…
1. Work on unit vocab sheet (front and back)
2. Do Jlab #5 Fixed set on device.
3. Watch BrainPop videos on Work/ Power