What is Newtons First Law

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Newton's First Law Inertia
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Objectives

• Students will be able to
• Distinguish between speed and velocity
• State Newtons first law and define inertia
• Use Studyworks and Moodle on line for tutorial
  help and taking quizes

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Sir Isaac Newton
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The Law of Inertia states that an object in
motion will stay in motion or at rest until a
force acts upon the object
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What do you think will happen to the objects on
this table when I give the tablecloth a quick
pull?
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Newtons Laws

• Newton developed 3 laws that explain the movement
  of objects
• Galileo was the first to experiment with the
  concepts of forces and speed
• Galileo defined speed as S d/t

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Speed is An Average

• Divide the distance to school by the amount of
  time it takes to get to school Average Speed
• Instantaneous speed (speedometer) may be
  different than your average speed.

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Velocity

• Velocity is different than speed
• Velocity is a measurement of speed and direction.

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Which Are Vector Quantities?

• a. 5 m
• b. 30 m/sec, East
• c. 5 mi., North
• d. 20 degrees Celsius
• e. 256 bytes
• f. 4000 Calories

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Problem

• An Olympic runner is timed at 9.98 s for the 100
  m dash.
• How fast did he run?
• S100 m/9.98 s
• 10.02 m/s

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Solve on your own

• What is the average speed of a cheetah that
  sprints 100 m in 4 s?
• What if the cheetah sprints 50m in 2 s?

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Last Problem

• How can you change this statement to make it
  shorter?
• She moves at a constant speed in a constant
  direction

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Online Tutorial

• The Physics Classroom StudyWorks Online
• http//www.physicsclassroom.com/Default.html

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StudyWorks Online

• Click on Physics Tutorial
• Click 1-D Kinematics in side bar
• Click on Lesson 1 Describing Motion with Words
• Read lesson one.
• Click on Speed

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Lesson 1 Speed and Velocity

• Read the Lesson on Speed and Velocity
• Click on the animation
• Do exercises 1 and 2
• Turn in written summary and answers to exercises.
• Take a quiz on this material

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Credits

• The Physics Classroom Studyworks Online
• http//www.physicsclassroom.com/Default.html
• Microsoft Encarta