Focus activity
What is the objective for this
week?
Objective 4 vocabulary:
inertia
acceleration
reaction
balanced force
unbalanced force
exerted
momentum
Sir Isaac Newton
Identify the illustrations showing
unbalanced forces and the illustrations
showing balanced forces. What is the
difference?
Newton’s Laws of Motion
Described the laws in
`Principia
Mathematica`written
in 1687
25 December 1642 – 20 March 1727
http://www.youtube.com/watch?v=cWOv7NyOnhY
Newton’s 1st Law of Motion
 An object will stay at
rest until acted on by
an outside force
 An object will stay in
motion at the same
speed until acted on by
a force
 Inertia is how much an
object resists a change
in motion
 Inertia = mass
http://www.youtube.com/watch?v
=8zsE3mpZ6Hw&feature=related
(car crash)
(*einkaufswagon & ball)
Newton’s 3rd Law of Motion
For every force
there is an equal
and opposite force
The foot pushes on the skateboard
and the skateboard pushes back on
the foot with an equal and opposite
force
What is another example of Newton’s
3rd law in these pictures?
http://www.physicsclassroom.com/Cl
ass/Newtlaws/U2L4a.cfm (QUIZ)
Lab questions
 Draw a force diagram of the canister in motion.
 Describe how Newton’s 1st law describes the
motion of the canister.
 Explain what caused the film canister to shoot
upwards using Newton’s 3rd Law.
 Describe how you could change the inertia of the
canister.
 Could this experiment work in space? Explain.
Newton’s 2nd Law of Motion
F=ma
 The force (F) on an
object is equal to
mass (m) of the object
multiplied by
acceleration (a) of the
object.
Newton’s 2nd Law balance
F
= ma
*Ping-pong
Lab questions
 Create a force diagram showing all of the forces acting on the
balloon as it accelerates across the string.
 According to Newton’s 1st law: an object in motion will stay at
the same speed until acted on by a force. Describe the forces
that slowed down the balloon as it moved along the string.
 Newton’s 3rd law states that for every action there is an equal
and opposite reaction. Describe where the action and reaction
forces were in this activity. (you should identify 3)
 Look at the table: describe at least 2 patterns in the circled and
underlined variables. How does one of the patterns relate to
the formula: F=ma?
 If the forces acting are equal and opposite, why does the
balloon move? (Hint: this is related to Newton’s 2nd law: F=ma)
Additional Videos & websites
 http://www.youtube.com/watch?v=UVdqxYyFRKY&featur
e=related (N1)
 http://www.physicsclassroom.com/mmedia/#forces (N1)
 http://www.ic.arizona.edu/~nats101/n2.html (N2)
 http://www.physicsclassroom.com/Class/Newtlaws/U2L4
a.cfm (N3)
 http://www.straightdope.com/columns/read/1846/howdo-rockets-work-in-the-vacuum-of-space (N3 and
rockets)