Physics 151 Week 8 Day 2
Topics
 Questions
 Models
 General Force Model
Newton’s 0th, 1st, and 3rd Laws of Motion
 Newton’s 2nd Law
 Force and Motion Graphs
Applying Newton’s Laws of motion
Nature of a Model
•
What was the model under debate for Columbus’
Voyage?
A. The world is flat vs. round
B. The size of the Earth
C. Something Else
•
Is a model of reality the same as reality?
General Force Model
Newton 0th Law
Objects are dumb - They have no memory of the past and cannot predict the
future. Objects only know what is acting directly on them right now
Newton's 1st Law
An object that is at rest will remain at rest and an object that is moving will continue
to move in a straight line with constant speed, if and only if the sum of the forces
acting on that object is zero.
Newton's 3rd Law
Recall that a force is an interaction between two objects. If object A exerts a force
on object B then object B exerts a force on object that is in the opposite direction,
equal in magnitude, and of the same type.
Visualizations:
• Force Diagrams
• System Schema
Net Force and Motion Graphs
Net Force vs. Acceleration Graphs
Net Force vs. Mass Graphs