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Force and Motion 7th
Focus Question
1. What is a force?
Name:________________
Grade Science-Study Guide
Detailed Explanation
FORCE IS A PUSH OR PULL
Real World Example: Draw a
Picture(caption) or Write in Words
1.
Pulling a wagon
2. Pushing a sofa to a
new spot in the room
2. What makes
something a
contact force and
how do the
following factors
affect contact
forces?
Makes a contact Force: Objects have to touch
3. What makes
something a noncontact force?
Makes a non-contact Force: No direct contact
Give 3 contact forces:
1. Friction
Mass: The more mass the more force needed
2. Air Resistance
3. Buoyancy
Surface Type: Friction: The rougher the surface, the more
contact force. Air friction.
Give 3 non-contact forces:
1. Gravity
Distance: The further the distance the weaker the force.
2. Magnetic Forces
3. Static Electricity
Focus Question
Detailed Explanation
Real World Example: Draw a
Picture(caption) or Write in Words
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4. How does a
contact force
causes a change in
motion?
5. How does a noncontact force
causes a change in
motion?
6. What is a
situation where two
forces act on an
object in the same
direction? Include
what happens to
the object’s speed
and direction.
Focus Question
You may draw and label a picture or write about a situation.
WHEN YOU HIT THE BALL, IT CHANGES DIRECTION
You may draw and label a picture or write about a situation.
GRAVITY IS CAUSING A CHANGE IN MOTION BY PULLING
THE SKYDIVERS TOWARD THE EARTH.
YOU AND A FRIEND ARE MOVING A DRESSER. THE FORCES YOU AND YOUR FRIEND
EXERT ON THE DRESSER ACT IN THE SAME DIRECTION. YOU ARE PUSHING AT 20N
WHILE YOUR FRIEND IS PULLING AT 25N. THE TWO FORCES ARE ADDED
TOGETHER TO DETERMINE THE NET FORCE BECAUSE THE FORCES ACT IN THE SAME
DIRECTION. IN THIS CASE, THE NET FORCE IS 45 N IN THE DIRECTION THE
DRESSER IS BEING PUSHED/PULLED.
Detailed Explanation
Real World Example: Draw a
Picture(caption) or Write in Words
Where can I find this?
*Lab
*Assignment
*Book page
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7. What is a situation
where two forces act
on an object in the
opposite and equal
direction? Include
what happens to the
object’s speed and
direction.
YOU ARE AT A PEP ASSEMBLY AND THE 7TH AND 8TH GRADERS ARE PLAYING TUG-AWAR. EACH TEAM IS PULLING WITH THE SAME FORCE AND THE FLAG IN THE
MIDDLE IS NOT MOVING.
8. What is a situation
where two forces act
on an object in the
opposite and unequal
direction? Include
what happens to the
object’s speed and
direction
9. How could you
illustrating balanced
(zero net) forces?
You must show an
object at rest and
one in constant
motion.
Focus Question
At Rest
In Constant Motion
ALL OF THE FORCES ON THE CARDS
ARE BALANCED. THAT IS WHY THE
CARDS DON’T MOVE.
A RACE CAR TRAVELING 145 MPH IN A
STRAIGHT LINE.
Detailed Explanation
Real World Example: Draw a
Picture(caption) or Write in Words
Where can I find this?
*Lab
*Assignment
*Book page
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10. How could you
illustrate
unbalanced (nonzero net) forces?
11. What is the
difference
between balanced
and unbalanced
forces?
12. How does the
mass of an object
affect the force
needed to change
the object’s
motion?
Focus Question
13. What are
Newton’s Laws of
FOR EXAMPLE, WHEN A SOCCER BALL IS KICKED IT RECEIVES AN UNBALANCED
FORCE. THE BALL CONTINUES TO ROLL ON THE GROUND LONG AFTER THE FORCE
OF THE KICK HAS ENDED.
BALANCED FORCES WILL NOT CAUSE A CHANGE IN A
MOVING OBJECT. AN OBJECT AT REST STAYS AT
REST. AN OBJECT IN CONSTANT MOTION IS ALSO A
BALANCED FORCE.
Balanced:
UNBALANCED FORCES CAUSE AN OBJECT TO CHANGE
DIRECTION, SPEED OR BOTH.
Unbalanced:
MASS IS A MEASURE OF INERTIA. AN OBJECT THAT
HAS A SMALL MASS HAS LESS INERTIA THAN AN
OBJECT THAT HAS A LARGE MASS. SO, CHANGING THE
MOTION OF AN OBJECT THAT HAS A SMALL MASS IS
EASIER THAN CHANGING THE MOTION OF AN OBJECT
THAT HAS A LARGE MASS.
A SOFTBALL HAS LESS
MASS AND THEREFORE
LESS INERTIA THAN A
BOWLING BALL. IT’S
MUCH EASIER TO THROW
A SOFTBALL THAN TO
THROW A BOWLING BALL.
Detailed Explanation
1ST LAW: AN OBJECT AT REST REMAINS AT REST, AND
AN OBJECT IN MOTION REMAINS IN MOTION AT
Real World Example: Draw a
Picture(caption) or Write in Words
-
Where can I find this?
*Lab
*Assignment
*Book page
PENNY ON A
FLICKED CARD OR A
1st Law:
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motion?
14. How would you
draw and describe
motion using a
reference point?
Focus Question
15. What is the
difference
CONSTANT SPEED AND IN A STRAIGHT LINE UNLESS
ACTED ON BY AN UNBALANCED FORCE. ALSO KNOWN AS
LAW OF INERTIA.
2ND LAW: THE ACCELERATION OF AN OBJECT DEPENDS
ON THE MASS OF THE OBJECT AND THE AMOUNT OF
FORCE APPLIED.
3RD LAW: WHENEVER ONE OBJECT EXERTS A FORCE ON A
SECOND OBJECT, THE SECOND OBJECT EXERTS AN EQUAL
AND OPPOSITE FORCE ON THE FIRST. ALL FORCES ACT IN
PAIRS—ACTION AND REACTION.
SEAT BELT
IT TAKES MORE
FORCE TO MOVE A SUMO
WRESTLER THAN A
TODDLER
2nd Law
ROCKET BLASTING
OFF GROUND
3rd Law:
1. The red flag would be a
Reference point.
Detailed Explanation
SPEED IS THE DISTANCE TRAVELED BY AN OBJECT
DIVIDED BY THE TIME TAKEN TO TRAVEL THAT
Real World Example: Draw a
Picture(caption) or Write in Words
Where can I find this?
*Lab
*Assignment
*Book page
Speed: A CAR IS
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between speed and
velocity?
DISTANCE. VELOCITY MUST INCLUDE A REFERENCE
DIRECTION.
TRAVELLING 60 MPH
Velocity: A CAR IS
TRAVELLING 60 MPH
SOUTH.
16. How could you
use the formula for
speed to describe
the motion of an
object? How could
you include velocity
in your problem?
Formula: Speed = Distance / Time
Sample problem:
A family makes a 400 mile road trip in 8 hours. What was their average speed during their trip?
400 miles / 8 hours = 50 miles/hour (mph)
Velocity: A family travels 3 hours north on I-75 for 210 miles. What was their velocity during
their trip?
210 miles / 3 hours = 70 mph North
Focus Question
17. If you’re on a
spinning ride at a
Detailed Explanation
Real World Example: Draw a
Picture(caption) or Write in Words
Where can I find this?
*Lab
*Assignment
*Book page
YOU WANT TO BE SITTING ON THE LEFT SIDE BECAUSE THE RIDE WANTS TO
TRAVEL IN A STRAIGHT LINE. BUT BECAUSE OF THE RESTRAINTS KEEPING IT IN
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carnival and the
ride rotates to the
left, which side of
the car do you want
to sit on so you
won’t get squished?
Explain your answer
(you may use a
diagram)
18. How would you
show an object
moving at a
constant speed, an
object at rest and
an object
accelerating on a
line graph?
19. What is energy
A CENTRIPETAL ROTATION, IT PULLS YOU BACK THEREFORE APPLYING PRESSURE
TO THE RIGHT SIDE OF THE CAR.
Bodies!!!
Ride spinning
to the left!
Inertia wants to send
you straight, but the
ride curves you to the
left. The person on the
right gets smashed!
D
i
s
t
a
n
Constant Speed
At Rest
D
i
s
t
a
n
c
c
e
Acceleration
Deceleration
D
i
s
t
a
n
c
e
e
Time
Time
Time
ENERGY IS THE ABILITY TO DO WORK. WORK IS DONE
WHEN A FORCE CAUSES AN OBJECT TO MOVE IN THE
DIRECTION OF THE FORCE.
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20. What is
Potential Energy?
POTENTIAL ENERGY IS THE ENERGY AN OBJECT HAS
BECAUSE OF ITS POSITION.
A STRETCHED BOW HAS
POTENTIAL ENERGY. THE BOW
HAS ENERGY BECAUSE WORK
HAS BEEN DONE TO CHANGE
ITS SHAPE.
21. What is Kinetic
Energy?
KINETIC ENERGY IS THE ENERGY OF MOTION. ALL
MOVING OBJECTS HAVE KINETIC ENERGY.
AN ARROW FLYING
THROUGH THE AIR.
22. What is an
example of each
type of energy?
Light
THERMAL
CHEMICAL
NUCLEAR
SOUND
ELECTRICAL
LIGHT ENERGY
IS PRODUCED
BY THE
VIBRATIONS OF
RADIATOR
CHEMICAL
COMPOUNDS
FOUND IN
FOOD
THE ENERGY
GIVEN OFF BY
THE SUN
COMES FROM
NUCLEAR
ENERGY.
SOUND ENERGY
IS CAUSED BY
AN OBJECT’S
VIBRATIONS. WHEN
YOU STRETCH A
GUITAR STRING,
THE STRING
STORES
POTENTIAL
GENERATORS
ELECTRICALLY
CHARGED
PARTICLES.
MICROWAVES ARE
A GOOD
EXAMPLE
23. What are two
examples of energy
conversion?
ENERGY.
AN ENERGY CONVERSION IS A CHANGE FROM ONE FORM OF ENERGY TO
ANOTHER. EX 1. ELASTIC POTENTIAL ENERGY: A RUBBER BAND STRETCHED
HAS POTENTIAL ENERGY AND WHEN LET GO, CHANGES TO KINETIC ENERGY
EX 2. CHEMICAL ENERGY OF FOOD IS CONVERTED INTO KINETIC ENERGY
WHEN YOU ARE ACTIVE. IT IS CONVERTED INTO THERMAL ENERGY TO
MAINTAIN BODY TEMPERATURE.
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