Bellringer

Insert Date CCSS: P.4E: Develop and interpret free-body force diagrams By the end of today, IWBAT… Develop and interpret free-body diagrams Essential Question: How do I visually represent forces? Topic: Free-Body Diagrams

Why it matters in LIFE: You already know how to calculate an object’s motion – now we are going to learn about WHY objects move Why it matters in LIFE: You already know how to calculate an object’s motion – now we are going to learn about WHY objects move Why it matters in THIS CLASS: Our Goal = 80% Mastering today’s lesson (focused participation, asking questions, etc) is the first brick that will help us reach our goal for this unit, and eventually for the year Why it matters in THIS CLASS: Our Goal = 80% Mastering today’s lesson (focused participation, asking questions, etc) is the first brick that will help us reach our goal for this unit, and eventually for the year By the end of the day today, IWBAT… Develop and interpret free- body diagrams By the end of the day today, IWBAT… Develop and interpret free- body diagrams

Quick Checks  What is net force?  What is true about net force when all the forces acting on an object are balanced?  What does this mean for the motion of the object?  What is true about net force when all the forces acting on an object are unbalanced?  What does this mean for the motion of the object?

Quick Checks  What is friction?  How do you know that friction must be a force?  What is gravity?  How do you know that gravity must be a force?  What is normal force?

What is a free-body force diagram?  Force is a vector quantity  the effect of a force depends on its magnitude and direction  We can draw forces as vectors ( ) to help us break down all the different forces that are acting on an object  Free body diagram = A diagram of an object that shows the size and direction of all forces acting on it

Part 1: DEVELOP FBDs

What forces are acting on the CARRIAGE?

How do we develop a free-body force diagram? Force of Gravity Force of the horse Force of Ground (Normal Force) FNFN F FgFg Force of Friction FAFA ( (Applied Force)

How do we develop a free-body force diagram?  Use these questions each time  Is there gravity? Fg  Is the object on a surface? FN  Is the object being pulled or pushed? Fa  Is there friction? Ff  Which way are all of these forces pulling the object?

Draw the free-body diagram of a soccer ball being kicked  What are the forces on the football?  Which way should the forces be drawn?

Draw the free-body diagram of a soccer ball being kicked  What are the forces on the football?  Which way should the forces be drawn? Force of Gravity FGFG FAFA Force of Kick Force of Ground (Normal Force) FNFN

Part 2: INTERPRET FBDs

Find the Net Force

Practice Finding the Net Force Net Force: __________ BALANCED or UNBALANCED? 0 N No direction

Practice Finding the Net Force Net Force: __________ 5 N Left BALANCED or UNBALANCED?

Practice Finding the Net Force Net Force: __________ 0 N No direction BALANCED or UNBALANCED?

Practice Finding the Net Force Net Force: __________ 15 N Up BALANCED or UNBALANCED?