Unit 2 CLASS NOTES
(Khan Academy Review Video)
Overview of Important Content in this Unit:
Intro to Forces
Forces - an interaction between two objects that results in a push or pull
"Types" of forces -
(Khan Academy Review Video)
Overview of Important Content in this Unit:
- Newton's First Law
- Newton's Second Law
- Newton's Third Law
- Identifying interactions: System Schemas and Force Diagrams
- Force Calculations
- Solving Force Problems
- Relating Representations of Motion and Force Models
- Solving Problems with Forces and Motion
Intro to Forces
Forces - an interaction between two objects that results in a push or pull
"Types" of forces -
SYSTEM SCHEMAS
- Draw the system schemas and the force diagram for THE BOOK
- Identify our system of interest
- Identify all of the objects that our system interacts with
- Shrink our system down to a dot
- Identify all interactions with our system
- Draw the system schemas and the force diagram for THE BOOK
Newton's First Law (of Inertia)
"An object will continue to move at a constant velocity unless it feels an unbalanced push or pull." ---- Mr.Frost
Inertia - An object's tendency to resist change in motion. Inertia is solely dependent on the MASS of the object
"An object will continue to move at a constant velocity unless it feels an unbalanced push or pull." ---- Mr.Frost
Inertia - An object's tendency to resist change in motion. Inertia is solely dependent on the MASS of the object
Bowling Ball Activity
There isn't a no-touch zone in this youtube video, but when we did it in class, the bowling ball kept moving in the same direction during the no-touch zone, and this is a result from inertia. When we used a lighter basketball instead of a bowling ball, the time got significantly faster, this proved that inertia is only dependent on the MASS of the object.
Newton's Second Law
Newton's Second Law Lab
The Lab proved that acceleration is directly proportional to total force and inversely proportional to total mass.
Therefore, if we put this relationship in a equation also proved by the Experiment we did, Newton's Second Law can be written as
Acceleration(m/s/s) = Net Force(N) / Mass(kg) --> a = ∑F / m
Newton's Third Law
Newton's Second Law Lab
The Lab proved that acceleration is directly proportional to total force and inversely proportional to total mass.
Therefore, if we put this relationship in a equation also proved by the Experiment we did, Newton's Second Law can be written as
Acceleration(m/s/s) = Net Force(N) / Mass(kg) --> a = ∑F / m
Newton's Third Law
Whenever two objects interact, each object exerts an equal force on the OTHER object. These forces are equal in magnitude but opposite in direction.
These forces are often referred to as Newton's Third Law Pairs. When identifying third law pairs remember:
Newton's Third Law Paradox
If every force has an equal and opposite reaction force, why don't those forces balance? In that case, shouldn't all forces be balanced?
Example Problem
These forces are often referred to as Newton's Third Law Pairs. When identifying third law pairs remember:
- When an object (Object A) exerts any force on another object (Object B), the third law pair according to Newton's 3rd Law is:
- Exerted BY the object receiving the original force (Object B)
- Exerted ON the object applying the original force (Object A)
- The same type of force/interaction as the original
Newton's Third Law Paradox
If every force has an equal and opposite reaction force, why don't those forces balance? In that case, shouldn't all forces be balanced?
- Because they act on different objects, two forces that are third law pairs will NEVER cancel out each other.
Example Problem
According to Newton's Third Law, the Answer to this question will be D.
Force Calculations
Solving Force Problems -- Force Calculation Booklet
Force Calculation Booklet.pdf | |
File Size: | 4757 kb |
File Type: |
Relating Representations of motion and Force Models
Solving Problems with Forces and Motion
Elevator Physics
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