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Chapter 11: Motion. Section 3. Standards. Standard 3 Motion Investigate the relationships among speed, position, time, velocity, and acceleration. Objectives. List the four fundamental forces of nature Explain the term net force Contrast balance and unbalanced forces
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Chapter 11: Motion Section 3
Standards • Standard 3 Motion • Investigate the relationships among speed, position, time, velocity, and acceleration
Objectives • List the four fundamental forces of nature • Explain the term net force • Contrast balance and unbalanced forces • Describe the two different types of friction • Explain the differences between wanted and unwanted friction
There are FOUR fundamental forces which are they? • Gravity • Friction • Wind/Water • Electromagnetic • Sliding • Attraction • Weak Nuclear • Solar • Static • Torsion • Strong nuclear • Field • Contact
Objective 1: List the four fundamental forces of nature And the FANTASTIC FOUR are… The IMPRESSIVE Twosome The TROUBLESOME Two Strong Nuclear Acts over short distances Strongest force Holds together the atomic nucleus Weak Nuclear Acts over short distances Responsible for radioactive decay • Gravity • Acts over large distances • Experienced every day • Electromagnetic • Acts over large distances • Deals with electricity and magnets
Objective 2: Explain the term net force TUG O WAR!! • Explain what happens! • Net force • Sum of all forces acting on an object • When net force acts on an object… • The object will accelerate in the direction of the force • Example: when playing tug of war the side that is pulling with the most force accelerates in the direction of the other side
Objective 3: Contrast balance and unbalanced forces The Balancing Act Balanced Forces Unbalanced Forces Net force is NOT equal to zero Cause an object To accelerate To change motion Examples Speeding up or slowing down in car Winning tug of war Circular motion! • Net force is equal to zero!! • Do NOT cause an object • To accelerate • To change motion • Examples: • Book sitting on a desk • You sitting in your chair • Moving at a constant speed in one direction
Objective 4: Describe the two different types of friction What Caused That?!? • FRICTION!!!!!!!!!! • Force that ALWAYS OPPOSES motion • Two types of friction • Static friction • Friction between surfaces that are stationary • Kinetic friction • Friction between surfaces that are moving • Two types • Sliding – when two objects slide against one another • Rolling – when a rounded object rolls over a flat surface • Is usually less than sliding friction • Static friction is always greater than kinetic friction!!!
Objective 5: Explain the difference between wanted and unwanted friction The Love/Hate of Friction! • Without Friction… • There would be NO movement!! • What are some ways that friction is helpful? • Walking, sitting in a desk, even writing with a pencil! • What are some ways that we can increase friction? • Making surfaces more rough • Putting sand on the roads or baseball players wearing gloves • What are some ways that friction can frustrate you? • In an engine-friction will rob horsepower or even burn up an engine! • Hinges in doors! The CREAKY door syndrome! • What are some ways to lower friction • The use of lubricants, such as grease or WD-40 • Using cooking oil on a pan while cooking