1. © 2010 Pearson Education, Inc. This lecture will help you understand: Newton’s Second Law of Motion Force Causes Acceleration Mass Resists Acceleration Acceleration is change in motion

2. © 2010 Pearson Education, Inc. The change in velocity is given by the expression… A.v i – v f B.v f – v i C.v i – 0 D.v f - 0

3. © 2010 Pearson Education, Inc. Newton’s Second Law of Motion Isaac Newton was the first to connect the concepts of force and mass to produce acceleration.

4. © 2010 Pearson Education, Inc. Newton’s Second Law of Motion Newton’s second law (the law of acceleration) relates acceleration to force. The acceleration produced by a net force on an object is directly proportional to the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object.

5. © 2010 Pearson Education, Inc. In the equation V=D/T, D is ________ to V. A.proportional B.inversely proportional

6. © 2010 Pearson Education, Inc. In the equation A=V/T, T is ________ to A. A.proportional B.inversely proportional

7. © 2010 Pearson Education, Inc. Newton’s Second Law of Motion

8. © 2010 Pearson Education, Inc. Acceleration Formulated by Galileo based on his experiments with inclined planes. Rate at which velocity changes over time

9. © 2010 Pearson Education, Inc. Acceleration In equation form: Unit of acceleration is unit of velocity / unit of time. Example: You car’s speed right now is 40 km/h. Your car’s speed 5 s later is 45 km/h. Your car’s change in speed is 45 – 40 = 5 km/h. Your car’s acceleration is 5 km/h/5 s = 1 km/h/s.

10. © 2010 Pearson Education, Inc. What is the change in velocity if an object from rest falls until it reaches 20m/s? A.-20 m/s B.10 m/s C.-10 m/s D.20 m/s

11. © 2010 Pearson Education, Inc. What is the change in velocity of an object that starts at 5m/s and ends at 20 m/s? [Default] [MC Any] [MC All] A.20 m/s B.25 m/s C.15 m/s D.100 m/s

12. © 2010 Pearson Education, Inc. Acceleration Involves a change in speed, or change in direction, or both. Example: Car making a turn

13. © 2010 Pearson Education, Inc. Determining Acceleration from Force StepProcessActionnotes 1 Determine forcesFBD – draw it!!Include all forces 2 Find Net Force Add forces on same axis  F = ? Separate forces into axis and add, (+ & -) 3 Use Newton’s 2 nd Law  F = maNeed m, a =  F/ m

14. © 2010 Pearson Education, Inc. Determining Acceleration from  v StepProcessActionnotes 1Determine what you are Given v i =, v f =, t =, a =Rest = 0 m/s 2Determine what your Unknown is ??? – what are they asking 3Put it in the Equation 4SolveThe answer is…