due next class: pre-read and redefine in your own words...
TRANSCRIPT
Do Now:
1. Walk in silently.
2. Grab a calculator and any papers for
today.3. Graph your retake mastery on your tracker
in the “E” column!
Due Next Class:
Pre-read and redefine in
your own words each
force on the back of the
“Types of Forces” paper
Created by M. Kelly OBJECTS IN MOTION STAY IN MOTION!
Based on the picture, what
do you think we are talking
about today?
Why it matters in LIFE:
Part of being a
functional human
being is being able to
understand what’s
happening in the world
around you!
Why it matters in THIS CLASS: Our Goal = 80%
Mastering today’s lesson (focused
participation, asking questions, etc)
is the first brick that will help us
reach our goal for this unit, and
eventually for the year
By the end of today, IWBAT…- Understand why objects move
- Define balanced and unbalanced
forces
- Understand Newton’s 1st and 2nd Law
- Understand inertia
TEKS:
4(D) calculate the effect of forces on
objects, including the law of inertia,
the relationship between force and
acceleration, and the nature of force
pairs between objects;
Topic:
Force and Newton’s
2nd Law
By the end of today, IWBAT…
-understand why objects move
-calculate force in simple
situations
A force is a
push
pull
or a
WHAT HAPPENS WHEN
YOU PUSH OR PULL
SOMETHING?
IT SPEEDS UP!
FORCE, F (units - Newtons, N)
A push or a pull on an object that
changes its velocity.
accelerationspeed up, slow down, or change direction
HOW MANY FORCES ACT ON THE
BASEBALL?
1 . PA R T NE R UP.
2 . G R A B 1 CH R OM E BO O K
P E R G R OUP.
3 . COM P L E T E T H E E N T I R E
L A B A N SW E R I N G I N
COM P L E T E
S E NT E NC E S .
“The acceleration of an object as produced by a net force is
directly proportional to the magnitude of the net force, in
the same direction as the net force, and inversely
proportional to the mass of the object.”
Σ𝐹 = 𝑚 ∗ 𝑎
∑F = sum of the forces (N)
m = mass (kg)
a = acceleration (m/s2)
NEWTON’S 2ND LAW
MASS, m (units - kilograms, kg)
The measure of matter in an object.
The mass of an object is the same no matter
where you are.
It’s an object’s weight that changes.
Examples
• Car driving at a
constant velocity
• You sitting in your
chair
• Arm wrestling
(when it’s tied)
Forces are balanced when the ∑F = 0
• NO ACCELERATION
• Object is said to be in equilibrium (∑F = 0, a = 0)
BALANCED FORCES
Examples
• Car pulling out of
the driveway
• You getting up out
of your chair
• Arm wrestling (when
someone is
winning)
UNBALANCED FORCES
Forces are unbalanced when ∑F ≠ 0
• Object is speeding up, slowing down, or
changing directions
NEWTON’S FIRST LAW!
AN OBJECT IN MOTION STAYS IN MOTION,
AND AN OBJECT AT REST STAYS AT REST
UNLESS ACTED UPON BY AN UNBALANCED
FORCE.
During video:
1. Listen carefully
2. Take quick notes *focus on inertia
https://www.youtube.com/watch?v=JGO_zD
Wmkvk
INERTIA
The tendency of an object to
resist changes in motion.
An object wants to keep doing what it’s already doing.
HOW DOES MASS EFFECT INERTIA?
The greater the mass of an object, the greater the net
force required to get it moving or to change its motion
Therefore, the greater the mass, the greater the inertia
Which has
the most
inertia?
WHITE BOARD PRACTICE!
A BALL ROLLING DOWN A HILL.
BALANCED OR UNBALANCED?
A BALL ROLLING WITH A
CONSTANT VELOCITY ACROSS A
TABLE.
BALANCED OR UNBALANCED?
THE SUM OF THE FORCES IS
ZERO.
BALANCED OR UNBALANCED?
A MAN PUSHING A BOX ACROSS
A FLOOR WITH NO
ACCELERATION.
BALANCED OR UNBALANCED?
AN APPLE FALLING TO THE
GROUND.
BALANCED OR UNBALANCED?
A SPACESHIP FLOATING
THROUGH SPACE WITH IT’S
ENGINE TURNED OFF.
BALANCED OR UNBALANCED?
THE OBJECT IS IN EQUILIBRIUM.
BALANCED OR UNBALANCED?
TWO METEORS COLLIDE IN
SPACE AND ARE REDIRECTED.
BALANCED OR UNBALANCED?
THE SUM OF THE FORCES IS NOT
ZERO.
BALANCED OR UNBALANCED?
JUMPING.
BALANCED OR UNBALANCED?
A CAR COMING TO A STOP AT A
STOPLIGHT.
BALANCED OR UNBALANCED?
A CHAIR OR A COUCH.
WHICH HAS MORE INERTIA?
TUG OF WAR (TIED).
BALANCED OR UNBALANCED?
A WHALE OR A FISH.
WHICH HAS MORE INERTIA?
THE MOON IN ORBIT AROUND
THE EARTH.
BALANCED OR UNBALANCED?
TUG OF WAR (ONE TEAM IS
WINNING).
BALANCED OR UNBALANCED?
A TENNIS RACQUET HITTING A
BALL.
BALANCED OR UNBALANCED?
A TEXTBOOK SITTING ON A DESK.
BALANCED OR UNBALANCED?
AN EMPTY BOWL OR A BOWL
FULL OF CEREAL.
WHICH HAS MORE INERTIA?
Which body is in equilibrium?
a) a satellite moving around Earth in a circular orbit
b) a cart rolling down a frictionless incline
c) an apple falling freely toward the surface of Earth
d) a block sliding at constant velocity across a
tabletop
EXIT TICKET1.
2.
3.
Summarize Newton’s 1st Law
and tell me it’s other name!