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March 20, 2014- Happy Spring!. Homework : Complete Will, Bill, and Phil worksheet- Read over Fig. 3 on page. 39 in textbook Do Now: - Write down homework, put worksheet in notebook- glue in later
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March 20, 2014- Happy Spring! • Homework: Complete Will, Bill, and Phil worksheet- Read over Fig. 3 on page. 39 in textbook • Do Now: -Write down homework, put worksheet in notebook- glue in later • Update T.O.C: pg: 1: The nature of Force, pg 2: Combining Forces: Net Force/ Unbalanced Forces • Open Textbook to pg. 36- Open NB. To pg 89/1
Chapter 2- Forces The Big Idea: Motion and Forces Essential Question (EQ): What causes an objects motion to change?
The nature of force • Where does it all begin? • What causes an object to start moving, stop moving or change direction? Force -Is a push or a pull- exerted by one object onto a second object. -Forceis described by its strength and direction and these are symbolized with an arrow
The strength and direction a can be represented with an arrow • Points in the direction of the force • The length of the arrow shows its strength. **The longer the arrow the greater the force**
The Newton (N) • The strength of a force is measured in the SI unit called a newton (N) • One newton of force = lifting up a small lemon
Net Force/ (un)Balanced Forces • Net Force – the combination of all the forces acting on an object-Determines if the object moves and which direction it moves in- It always acts in the direction of the greatest force. • Unbalanced force:-} Can cause an object to start moving, stop moving or change direction- results in a net force and causes a change in motion • Balanced Forces:-} Equal forces acting on one object in opposite directions- there is no change in motion and no net force
Tug-of-war? If the net force is anything other than zero (0)- forces are unbalanced and there is a change in motion
Combining forces( pg. 2 in Notebook) • Look at Fig. 2 on pg. 37: • When the two arrows are going in the same direction they are added together to find the net force • Two forces act in opposite directions- they are subtracted (or like adding a positive # to a Negative #) • *The net force ALWAYS acts in the direction of the greatest force.* • A net force of zero (0) --the forces are balanced- no change in motion
Is the force Balanced or unbalanced? Unbalanced- What is the net force and in which direction is it going in?