Transcript Newton`s First Law of Motion

Chapter 2
Motion in One Dimension
Topics:
•
The kinematics of motion in
one dimension
•
•
Problem-solving strategies
Motion Diagrams and
Pictorial Diagrams
Sample question:
Horses can run much much faster than humans, but if the length of
the course is right, a human can beat a horse in a race. When, and
why, can a man outrun a horse?
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The Sprinter
A sprinter accelerates at 2.5 m/s^2 until reaching his top speed
of
15 m/s. He then continues to run at top speed.
How long does it take him to run the 100 m dash?
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Down and up
A ball is released on the left side at a height of 1 m on a
frictionless 30 degree slope, |a| = 5 m/s2. At the bottom, it turns
smoothly onto a 60 degree slope going back up, |a| = 8.66
m/s2.
What maximum height does it reach on the right side?
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Brainstorm: What is a Force?
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Galileo (1564-1642)
Developed the idea of experimental
science
Re-examined natural motion of objects and
how objects move
Made astronomical observations that
challenged Earth-centered solar system
model.
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Newton (1642-1727)
Newton's work based on experiments of how
objects interact.
His laws of motion and law of gravity described
how all objects interact with each other.
Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley.
Newton’s Zeroeth Law of Motion
Objects are dumb - They have no memory of the past and
cannot predict the future. Objects only know what acts
directly on them in a given moment.
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Newton's Zeroeth Law of Motion
DEMO - Pushing the cart on track
Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley.
Newton's First Law of Motion
Every object continues in a state of rest or a state of motion with a
constant speed in a straight line unless acted on by an unbalanced
force.
Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley.
Newton's First Law of Motion
DEMO - Air Puck motion
DEMO - Smash the HAND
DEMO - Tablecloth
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Newton's Second Law of Motion
When a force, Fnet, acts on an object with a mass, m, it produces an
acceleration, a, equal to the force divided by the mass.
a=
Fnet
m
acceleration is a change in speed or a change in direction of speed.
Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley.
Identifying Forces:
Freebody (Force) Diagrams and System Schema
Michael
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Laura
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