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

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)http://www.youtube.com/watch?v=gkcidRnzGfc

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) http://www.wimp.com/tugwar/

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) http://www.youtube.com/watch?v=VCoTiV1STQ4

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)