UNIT CF: Class 1

Start

30:00

Agenda

• PREASSESSMENT

• CF: ACTIVITY 1

• BREAK

• CF: ACTIVITY 2

• CONCEPT MAP

• CER TICKET

activity 1

In this exploration you will use the simulator model to examine scientists’ ideas about the effect that a combination of two forces has on an object that is initially at rest. You will also consider whether a single force, acting on an otherwise identical cart, could have exactly the same effect.

Movie 1

Simulation: Two fan forces pointed in same direction (stationary cart)

Movie 2

In this exploration you will use the simulator model to examine scientists’ ideas about the effect that a combination of two forces has on an object that is initially at rest. You will also consider whether a single force, acting on an otherwise identical cart, could have exactly the same effect.

Movie 3

Two fan forces pointed in opposite directions (moving cart)

Movie 4

Simulation: Stronger backward force on moving cart

Movie 5

Simulation in Movie 4 run several seconds longer

In the previous activity you saw that when an unbalanced combination of forces acts on an object, the speed of the object changes, which is the same as what happens when a single force acts on it. But what if the combined strength of the forces pushing (and/or pulling) in one direction is exactly equal to the combined strength of the forces pushing (and/or pulling) in the opposite direction? In this case we say the forces are balanced.

activity 2

Movie 1

Simulations of balanced fan forces on cart (various scenarios)

concept map

How does an object behave when the forces acting on it are balanced?

+ info

Unbalanced and Balanced Forces