Transcript Force and Motion Vocabulary

Activator
Write the question and answer:
• What do you think of when you hear the
word “force?”
Force
SPS8. Students will determine relationships
among force, mass, and motion.
b. Apply Newton’s three laws to everyday situations
by explaining the following: Inertia; Relationship
between force, mass and acceleration; Equal and
opposite forces
c. Relate falling objects to gravitational force
d. Explain the difference in mass and weight.
Force
Definition
• Any push or pull that could cause a
change in motion.
Force
Examples
•
•
•
•
•
•
•
Applied
Frictional
Electrostatic
Magnetic
Gravitational
Nuclear
Normal
Net Force
Definition
• The sum of all the forces in a system
Net Force
Examples
• Sitting in a chair – net force = 0
• Playing tug of war and team A pulls with
100 N, the team B pulls with 75 N – net
force = 25 N in the direction of team A
Balanced Forces
•
Definition
A condition when opposite forces acting
on an object are equal. The net force
acting on the object is zero.
Balanced Forces
Example
• A car engine is applying a forward force
400 N and the friction acting against the
car is 400 N. The forces acting on the car
are balanced and the speed does not
change.
Unbalanced Forces
Definition
• A condition when opposite forces acting
on an object are not equal. The net force
acting on the object is not zero.
Unbalanced Forces
Example
• A car engine is applying a forward force
800 N and the friction acting against the
car is 400 N. The forces acting on the car
are unbalanced and the speed of the car is
changing.
Speed
Definition
• The distance an object travels during an
amount of time
Speed
Example
• The speedometer in a car shows the
speed of the car.
Velocity
Definition
• The speed and direction in which an object
is moving
Velocity
Example
• You are traveling 70 miles per hour
northeast on the interstate
Acceleration
Definition
• The rate at which an object’s velocity
(speed) is changing over time.
Acceleration
Example
• A 2015 LaFerrari can go 0 mi/h to 60 mi/h
in 2.4 sec
Gravity
Definition
• A force of attraction between all objects
with mass
Gravity
Example
• Objects falling toward Earth
Weight
Definition
• The force of gravity acting on an object
Weight
Example
• Measured by a scale
Inertia
Definition
• The property of an object to resist change
in motion.
Inertia
Example
• A bucket full of sand is harder to push than
an empty bucket
TOTD
• Explain how each of the vocabulary words
we covered today were demonstrated in
the bowling ball activity.
Activator
Write the question and answer:
• How does a person win an arm wrestling
game (balanced or unbalanced forces)?
Why?
I will ask for volunteers to arm wrestle after
we finish the activator.
Force Diagrams
GPS8
Students will determine the
relationships among force, mass, and
motion.
Force Diagram
• A simple drawing that shows the forces
acting on an object. The object is
represented by a box. The direction of the
forces acting on the object are
represented by arrows.
Force Diagram
Example
Match the following descriptions
with the forces identified on your
handout:
1. Force from a solid surface that acts
opposite to gravity.
2. Force applied through a rope.
3. Force resisting motion.
4. A push or a pull acting on an object.
5. Force pulling all objects to the center of
Earth.
Practice 1
A book is at rest on a tabletop.
FN
Fg
Practice 2
A flying squirrel is gliding (no wing flaps)
from a tree to the ground at constant
velocity. Consider air resistance.
Fair
Fg
Practice 3
A rightward force is applied to a book in
order to move it across a desk with a
rightward acceleration. Consider frictional
forces. Neglect air resistance.
FN
Ff
Fapplied
Fg
Practice 4
A skydiver is descending with a constant
velocity. Consider air resistance.
Fair
Fg
Practice 5
A car is coasting to the right and slowing
down.
FN
Ff
Fg
Practice 6
An egg is free-falling from a nest in a tree.
Neglect air resistance.
Fg
Practice 7
A rightward force is applied to a book in
order to move it across a desk at constant
velocity. Consider frictional forces. Neglect
air resistance.
FN
Ff
Fapplied
Fg
Activator
Define the following forces in your own
words.
• Applied Force
• Frictional Force
• Normal Force
• Gravitational Force
• Tensional Force
• Air Resistance Force
Diagram/Describe the Forces
Acting Upon the Object
A bicycle is parked in a driveway. Diagram
the forces acting on the bicycle.
Diagram/Describe the Forces
Acting Upon the Object
A car engine is applying a forward force 400
N and the friction acting against the car is
400 N.
Diagram/Describe the Forces
Acting Upon the Object
A gymnast is holding onto a rope that is
attached to the ceiling and she is
motionless. Diagram the forces acting on
the girl as she holds on to the rope.
Diagram/Describe the Forces
Acting Upon the Object
An apple is free-falling from a tree. Neglect
air resistance. Diagram the forces acting
on the apple as it falls.
Diagram/Describe the Forces
Acting Upon the Object
A car engine is applying a forward force 800
N and the friction acting against the car is
400 N.
Diagram/Describe the Forces
Acting Upon the Object
An egg is falling (not freely, do not neglect
air resistance) from a nest in a tree.
Diagram the forces acting on the egg as it
falls.
Diagram/Describe the Forces
Acting Upon the Object
A leftward force is applied to a cellphone
in order to move it across a desk with a
rightward acceleration. Consider frictional
forces. Neglect air resistance. Diagram the
forces acting on the cellphone.
Diagram/Describe the Forces
Acting Upon the Object
A car is stopped at a stop light.
Diagram/Describe the Forces
Acting Upon the Object
A skydiver is descending with a constant
velocity. Consider air resistance. Diagram
the forces acting upon the skydiver.
Diagram/Describe the Forces
Acting Upon the Object
A car is parked on a sloped street.
Diagram/Describe the Forces
Acting Upon the Object
A hot air balloon is accelerating upward,
neglect air resistance.
Diagram/Describe the Forces
Acting Upon the Object
A car is coasting to the right and slowing
down. Diagram the forces acting upon the
car.
Calculate the net force
5
+
5
=
10
5
+
-5
=
0
5
+
10
=
15
10
+
-5
=
5
Calculate the net force
Fnet is 400 N, up
Calculate the net force
Fnet is 200 N, down
Calculate the net force
Fnet is 20 N, left