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.

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 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

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 Therefore, 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)

FN

FF

Fg

Force of Friction

FA

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 GravityFG

FA

Force of Kick

Force of Ground (Normal Force)FN

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?