Download File newtons 1st and 2nd law 2015

TOC: Newton’s Laws of Motion
12/1/2015
Set up your foldable like this!!!!
Newton’s First Law of Motion
• What does this really mean?
– An object at rest will stay at rest, and an object in motion will stay in motion
at constant velocity, unless acted upon by an unbalanced force.
• Inertia
– Tendency of an object to resist a change in motion
– Inertia means that the object’s motion will stay constant in terms of speed
and direction
– Depends on the mass of an object
– Does NOT depend of the presence of gravity
• An object’s inertia is the same on Earth and in space
– Objects with a greater mass have greater inertia
Examples of the Law of Inertia
If an object is in motion, it will keep going until something stops it. How
would vehicle restraints help in this situation?
http://www.nsf.gov/news/special_reports/football/law
ofmotion.jsp
Newton’s 1st law demo
• https://www.youtube.com/watch?time_conti
nue=100&v=0oyJmFe3ffg&noredirect=1
• https://www.youtube.com/watch?v=1_EV2KE
nqoQ
Check for Understanding
• Restate Newton’s First Law of Motion in your own
words.
• What is inertia?
• What are some examples of Newton’s First Law of
Motion?
Which object has the greater inertia?
TOC: Newton’s Laws of Motion
12/2/2015
Newton’s first law REVIEW
Summarize what the law states.
What does an object at rest need for it to move?
What is another name for Newton’s first law of motion?
What is inertia?
What causes a moving object to stop moving?
The (more/less) mass an object has, the harder it is to move.
The (more/less) mass an object has, the harder it is to move.
Newton’s 2nd Law
The acceleration of an object depends on the
mass of the object and the amount of force
applied
An object with a smaller mass has LESS INERTIA
Easier to accelerate a small mass
More difficult to accelerate a large mass that has more inertia
F = force (N)
m = mass (kg)
a = acceleration (m/s2)
Part 1: Acceleration depends on mass
Acceleration of an object decreases as its
mass increases
Acceleration of an object increases as its
mass decreases
Which would
be easier to
push?
WHY?
Newton’s law with MATH
Formula:
Force
F= M x A
mass
acceleration
UNITS 
acceleration: m/s² (meters per second squared)
force: N
(Newtons)
mass: kg
(kilograms)
More examples of the Law of Force and Acceleration
Roller Coaster
http://iws.collin.edu/mbrooks/stude
nt%20research/projects/Rollercoas
ter%20Simulation/index.html
Baseball: home run vs. bunt
http://www.youtube.com/watch?v=kZMuMd64j6U
http://www.youtube.com/watch?v=FiMIY3J5XTw
Football
http://www.nsf.gov/news/special_reports/f
ootball/newtonsecondlaw.jsp
Check for Understanding
• Restate Newton’s Second Law in your own words.
• Which would require a greater force to
accelerate? WHY?
– A hockey puck on ice or a hockey puck on uncut grass?
– An empty suitcase or a suitcase full of bricks?
• If the mass of a rock is doubled, what happens to
its acceleration if the force does NOT change?