1. NATURE OF FORCE
CHAPTER 2, SECTION 1
Page 36 – 39

2. WHAT IS A FORCE? A FORCE is a __PUSH__ or a __PULL__.
Like VELOCITY and ACCELERATOIN, a __FORCE__ is described by its __STRENGTH__ and by the __DIRECTION__ in which it acts.
The strength of a force is measured in the SI unit called the __NEWTON__.
The DIRECTION and STRENGTH of a force an be represented by an __ARROW__.
The __LENGTH__ of the arrow tells you the strength of a force.
The __LONGER__ the arrow, the
greater the force.
Eureka! (Acceleration due to force)

3. COMBINING FORCE
The combination of ALL forces acting on an object is called the __NET FORCE__.
The NET FORCE determines whether an object __MOVES__ and also in which __DIRECTION__ it moves.
When forces act in the same direction, they can be __ADDED__ together to produce a larger NET FORCE than either original force.
5 + 3 = __8 __
When forces act in the opposite direction, they will be __SUBTRACTED__ from each other.
6 – 3 = __3__
2 – 9 = __7__
If the opposing forces are of equal strength, there is __NO NET FORCE__
There is __NO CHANGE__ in the object’s motion.
4 – 4 = __0__
Tug of War with Monster Trucks (0:27)

4. UNBALANCED FORCES
__UNBALANCED FORCES__ can cause an object to __START__ moving, __STOP__ moving, and __CHANGE__ direction.
Unbalanced forces acting on an object result in a __NET FORCE__ and cause a __CHANGE__ in the object’s motion.
Arm Wrestling (gone wrong) (1:08)

5. BALANCED FORCES
__EQUAL__ forces acting on one object in opposite directions are called __BALANCED FORCES__.
__BALANCED FORCES__ acting on an object __DO NOT__ change the object’s motion.
Brain Pop – Force (3:00)