Transcript Forces! - Northwest ISD Moodle

Hmmm…
FORCE!
Hmmm…
FORCE!
Hmmm…
FORCE!
Hmmm…
FORCE!
Hmmm…
FORCE!
Hmmm…
FORCE!
Hmmm…
FORCE!
Hmmm…
FORCE!
Um, dream on, Joe.
This is more like it.
Yep. That’s force.
#1 FORCE
What’s happening to this bobsled?
You’d probably say that
it’s being pushed forward.
What’s happening to
this dogsled?
Yeah, it’s definitely
being pulled along.
#2 So, let’s define Force
So…anything you can think of that is a push or a pull…like
the air blowing from the air conditioner in the room to a leopard
dragging away its kill is showing force at work.
(write your name)
Notes – Force
I. Force – a push or a pull.
#3 What are some examples of
forces?
Here are some examples…think about how each is
a push or pull:
•Gravity
• Magnetism
•Friction
#4 Write it
Notes – Force
I. Force – a push or a pull.
•examples: gravity, magnetism,
friction
#5 Force Amounts
Forces come in different amounts. You’d much
rather be punched by your little sister than this guy:
We measure forces using the unit “newton.” Newton
is abbreviated with a capital N.
•3 miles = 3 mi
•4 gallons = 4 g
•2.4 liters = 2.4 L
•5 newtons = 5 N
FYI…a newton isn’t very much. It takes about 4.5 N
to equal a pound of force.
#6 Measuring Force
The precise amounts of force exerted are usually measured with tools
like these:
Notes – Force
I. Force – a push or a pull.
•examples: gravity, magnetism,
friction
•measured in a unit called “newton” (N).
#7 Combined Forces
Joe’s dog, Rex, lost his squeaky toy under the fridge. Joe wants to
get it for him.
#8 Joe Tries the Force…
…clearly,
the fridge does
not move.
#9 Joe Puts some Elbow Grease
Into it…he pulls!
…and since a force is both an amount and a direction, we
can use an arrow to symbolize it.
…but the fridge doesn’t
move. Somebody explain
why?
200N
200N
Right! Friction
between the fridge
and floor is the same
amount as Joe’s force.
We call this balanced
forces.
#10 Balanced Forces
Balanced forces exist when two or more forces combine to be in
opposite directions but the same amount. The overall effect is that
they cancel each other out.
50N
30N 20N
A tug-of-war usually starts
out featuring fairly balanced
forces. Well, at least for a
second or two.
#11 Write it!
Notes – Force & Newton’s Laws
I. Force – a push or a pull.
•examples: gravity, magnetism,
friction
•measured in a unit called “newton” (N).
A. Balanced Forces – cancel each other out
and do NOT change an object’s motion
#12 The Tug-of-war gives Joe
an Idea…
Pull, boy,
pull!
500N
200N
200N
#13 With 700 total newtons
pulling against 200 newtons…
That’s the beauty of unbalanced forces!
#14 Unbalanced Forces
Unbalanced forces exist when forces on an object do not cancel
each other out. This will result in an acceleration of some sort
(a change in motion such as speeding up, slowing down, or changing
directions).
25N
10N
20N
Yeah. Tug-of-wars aren’t really
any fun until unbalanced forces
result in victory and defeat.
#15 Write it down
Notes – Force
I. Force – a push or a pull.
•examples: gravity, magnetism,
friction
•measured in a unit called “newton” (N).
A. Balanced Forces – cancel each other out
and do NOT change an object’s motion
B. Unbalanced Forces – don’t cancel, so they
result in a change in motion
Man. That’s a lot of information about forces.
Just remember that a force is a push or a pull,
and that when unbalanced forces act on objects,
they cause a change in motion.
What Is Force?
It takes a force to move something.
A force is a push or a pull . . .
that causes an object to move,
stop, or change direction.
When you push an object,
it moves away from you.
When you pull an object, it moves toward or
with you.
Is this a push or a pull?
Is this a push or a pull?
Is this a push or a pull?
Is this a push or a pull?
Is this a push or a pull?
Is this a push or a pull?
Is this a push or a pull?
Is this a push or a pull?
What is the pulling force called?
Some Types of Forces
• Gravity
• Friction
• Magnetism
Gravity
Gravity:
the force that pulls all objects in the universe
towards each other’s center.
Gravity
The mass of an object determines how much
gravity that object has. For example:
The moon and Earth are pulling on each other. The Earth is
bigger than the moon so its gravitational pull is stronger. That
is why the moon orbits the Earth. What would happen if the
moon was bigger than the Earth?
Friction
Friction . . .
a force that acts against something when two
surfaces rub against each other.
A softball player sliding into home on the
rough dirt has a lot of friction and can stop.
A sled on smooth ice will keep sliding and is
hard to stop because it has only a little
friction.
What causes the leaves to fall to the ground during the Autumn season?
push
magnetism
gravity
What causes the leaves to fall to the
ground during the autumn season?
A. Magnetism
B. A pushing force
C. Gravity
D. Erosion
What causes the leaves to fall to the ground during the Autumn season?
push
magnetism
gravity
The moving of an object is called -A. force
B. friction
C. magnetism
D. gravity
What causes the leaves to fall to the ground during the Autumn season?
push
magnetism
gravity
Which of the following is an example of a
force that is different from gravity?
A. an apple dropping to the floor
B. a boy slamming a door
C. a leaf falling to the ground
D. water dripping from a faucet
What causes the leaves to fall to the ground during the Autumn season?
push
magnetism
gravity
What force is represented in the above
picture?
A. A pushing force
B. A pulling force
C. A magnetic force
D. Both A and C