3.5 - 3.7 PPT for Student Notes PDF

Section 5 Newton’s Second Law Links Force, Acceleration, and Mass  Newton’s Discovery First to realize the connection between force and mass in producing acceleration. Newton’s 2nd Law of Motion… The acceleration produced by...

Section 5 Newton’s Second Law Links Force, Acceleration, and Mass  Newton’s Discovery First to realize the connection between force and mass in producing acceleration. Newton’s 2nd Law of Motion… 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, Visualize It ◻ N m/ kg s2 2nd Law Math Wrapping it Up Acceleration = Net Force / Mass If you double the net force, then you double the acceleration. If you double the mass, then you cut the acceleration in half. If you double both the net force and the mass, then the acceleration remains the same. When you arrive… PICK UP: ⬜ Review half sheet NOW: ⬜ Work on review half sheet HAPPY THURSDAY! ⬜ You may ask a buddy!  Section 3.6 Friction is a Force That Affects Motion Friction Affects Motion Friction: the force that resists motion or attempted motion of an object (when the two objects touch) …occurs for solids, liquids, and gases …always acts in the opposite direction of motion  Concept Check Two forces act on a bowl resting on a table: the bowl’s weight and the support force from the table. Does a force of friction also act on the bowl? Suppose a high-flying jumbo jet flies at constant velocity when the thrust of its engines is a constant 80,000 N. What is the acceleration of the jet? What is the force of air drag acting on the jet?  Friction Force 1. Friction force varies with different pulling strengths. (LIKE SUPPORT FORCE!) 2. When the pull is too small to move the crate, friction equals the pull (Net Force = 0) 3. As the pull is increased, friction increases the same (Net Force = 0) 4. When the pulling force is greater than the friction (Net Force > 0), the crate accelerates. 5. Once the crate is moving, the pull can be reduced until it matches the friction, and the crate moves steadily. (Net Force = 0)  Section 3.7 Objects in Free Fall have Equal Acceleration  Remember Galileo’s experiment at the Leaning tower of Pisa? Free fall acceleration does NOT depend on mass ⬜ On any inclined plane, a ball has the same acceleration ⬜ also true for free fall But… Galileo couldn’t explain WHY accelerations were equal (Isaac Newton’s 2nd law does… in 3.8!) Acceleration and Mass  Conclusion Without air drag and at the same location, all objects fall with the same acceleration. Galileo demonstrated it, but Newton explained it