Force and Motion Class Notes 2 PDF

Force and Motion Class Notes 2 NET FORCE The combination of all forces acting on an object BALANCED FORCES Forces that are equal in size and opposite in direction UNBALANCED FORCES Forces that are NOT equal in size and/or opposite in direction Very IMPORTANT! 1. When an object experiences zero net...

Force and Motion Class Notes 2 NET FORCE The combination of all forces acting on an object BALANCED FORCES Forces that are equal in size and opposite in direction UNBALANCED FORCES Forces that are NOT equal in size and/or opposite in direction Very IMPORTANT! 1. When an object experiences zero net force (balanced forces), its speed and direction of motion are constant 2. When an object experiences a nonzero net force (unbalanced forces), some aspect of its acceleration - speed and/or direction of motion – will always change 3. Any object that is not traveling at a constant speed and direction must be in a situation where there is a nonzero net force (unbalanced forces) acting on it. Remember Motion Graphs? Describe what the vehicle does during each segment of the graph. Newton’s Laws of Motion What is Friction? What is Friction Coefficient? The ratio between the force required to move two sliding surfaces over each other and the force holding them together (Experiment with a marble, book, and a stapler moving down a ramp) Symbolized μ Measuring unit? None! (Adimensional) Types of Friction: Static Dynamic (sliding, rolling, fluid friction) Factors that influence Friction – Type of Surface, Shape of the object(s), mass (= weight/pressure) Center of Mass Definition: The center of mass or center of GRAVITY is the point where if an object is suspended, that object should not move but remain in static equilibrium (same position as on the ground) For a uniform object, such as a sphere, the center of mass will be at the exact geometric center For an irregularly shaped object, the center of mass will be closer to the part with more mass Please note: The center of mass is a LOCATION, NOT a mass! Draw three identical barrels, one empty, one half-full, and one full of oil a. Place an “X” on each barrel to show the approximate location of its center of mass b. Label the barrel that has the most mass “most mass” c. Label the barrel with the lowest center of mass “lowest center of mass.” Explain why the center of mass is located there d. Label the barrel that is easiest to tip over “least stable.” Then explain why that barrel is the least stable - What are the factors that affect the braking distance? - What is the force that ultimately stops any vehicle?