Do Now:
Homework to be Completed:
Todays Agenda:
PhET Gravity Activity Worksheet
Complete activtyGravity Force Lab - Basics
Check and Review in Class
Rocket Project!
Fin and Nose Cone Construction
How to make a cone.
Construction Stands
This is the daily classroom agenda for Paxton Center School Grade 7 Science. Lesson plans, homework, and other relevant information will be posted here each class.
Check and Review in Class
Read “Rocket Design Basics “ in the Rocket Man document and be prepared to answer a few basic questions about:
What forces affect a rocket?
What design strategies will help make a rocket perform better?
Check and Review in Class
Finish as Needed and Share
Why don’t people fall off the other side.
Class Check - self grading
Score
Pass in
Review in Clever
Discuss contact vs noncontact force
Notes?
PhET Gravity Activity Worksheet
Share
Complete in Clever - backup option will be GC
Project Planning
Issue Materials
store in locker
no construction
Calculate the net force on the ball.
Calculate the acceleration of the ball.
Calculate the weight of the ball in Newtons on Earth.
Quiz Thursday - Newton’s Laws of Motion
Review
Team Formation
Materials Check
When one object exterts a force on a second object, the second object exerts and equal force on the first object in the opposite direction.
for every action there is an equal but opposite reaction.
action - the initial force
reaction - the equal but opposite push back
act on different objects (sketch)
because action and reaction act on different objects - they sometimes behave very differently.
Examples:
ball bounce
standing on floor
action and reaction make a force pair.
Forces always occur in pairs.
normal force is a reaction force to pushing against a surface
When one object exterts a force on a second object, the second object exerts and equal force on the first object in the opposite direction.
for every action there is an equal but opposite reaction.
action - the initial force
reaction - the equal but opposite push back
act on different objects (sketch)
because action and reaction act on different objects - they sometimes behave very differently.
Examples:
ball bounce
standing on floor
action and reaction make a force pair.
Forces always occur in pairs.
normal force is a reaction force to pushing against a surface
Calculating Force and Weight with Newton’s Second Law
Calculating Force and Weight with Newton’s Second Law
The acceleration of an object is equal to the Net force acting on it divided by its mass
A = Fnet/M.
If mass increases, acceleration becomes less
If mass decreases, acceleration becomes more
Example problem in slide show.
Example Problem(s)
What is the acceleration of a skateboarder with a mass of 50 kg who us pushing with a net force of 100 N?
What is the acceleration of a 100 kg skydiver who has a net force of gravity pulling him downward with a net force of 980 N?
McGraw Hill Practice - complete this worksheet in class.
All student’s to complete the mass/weight article for HW
If the net force acting on an object is zero, motion does not change.
does not mean there is no motion - just no CHANGE in motion
stopped or constant velocity
Also called Law of Inertia
inertia is the tendency of an object to resist motion in proportion to its mass
objects do not change motion unless an unbalanced force acts upon them.
Balanced forces - net force = 0
object at rest
object maintains constant speed and direction (velocity)
Unbalanced froces (Net force >0)
object speeds up
object slows down
object turns
The acceleration of an object is equal to the Net force acting on it divided by its mass
A = Fnet/M. also F = M x A
If mass increases, acceleration becomes less
If mass decreases, acceleration becomes more
Essential Questions:
What forces affect these objects in he demonstrations?
What does the behavior of the objects tell us about the strength of those forces (relative to each other)?
Why do different objects move differently in these experiments?
Net Force is the combination of all forces acting upon a body.
When forces act together in the same direction, they are added.
When forces act in opposite direction, the are subtracted.
Vectors are used as a way to identify the direction and magnitude (strength) of the net force.
example
use vectors to determine the net force on a car with an applied force of 1500 N acting to the right moving it forward and a friction force of 2000 N acting to the left.
Also, assign forces a sign (+/-) based on their direction (just like a coordinate system)
+for right and up
- for left and down
Example
use vectors to determine the net force on a model rocket with an applied force of 1000 N acting upward and a friction force of 250 N acting downward.
If time permits:
Net Force is the combination of all forces acting upon a body.
When forces act together in the same direction, they are added.
When forces act in opposite direction, the are subtracted.
Vectors are used as a way to identify the direction and magnitude (strength) of the net force.
example
Also, assign forces a sign(+/-) based on their direction (just like a coordinate system)
+for right and up
- for left and down
Example