Presentation on theme: "Chapter 2 Motion 2-8. Mass 2-9. Second Law of Motion 2-10. Mass and Weight 2-11. Third Law of Motion 2-12. Circular Motion 2-13. Newton's Law of Gravity."— Presentation transcript:
Chapter 2 Motion 2-8. Mass 2-9. Second Law of Motion 2-10. Mass and Weight 2-11. Third Law of Motion 2-12. Circular Motion 2-13. Newton's Law of Gravity 2-14. Artificial Satellites 2-1. Speed 2-2. Vectors 2-3. Acceleration 2-4. Distance, Time, and Acceleration 2-5. Free Fall System 2-6. Air Resistance 2-7. First Law of Motion
2-1. Speed Definitions: –Speed The rate at which something moves a given distance. Faster speeds = greater distances –General formula for speed: Speed = distance / time Abbreviations commonly used: d = distance t = time v = speed v = d/t
2-1. Speed Velocity Distance Time
2-1. Speed Average speed is the total distance traveled by an object divided by the time taken to travel that distance. Instantaneous speed is an object's speed at a given instant of time.
2-2. Vectors Velocity is a vector quantity that includes both speed and direction.
2-3. Acceleration Acceleration of an object is the rate of change of its velocity and is a vector quantity. For straight-line motion, average acceleration is the rate of change of speed:
2-3. Acceleration 3 Types of Acceleartion Speeding Up Slowing Down Turning
2- 4. Distance, Time and Acceleration (V 1 + V 2 ) V avg = 2 d = v avg t d = ½at 2 (20 mph + 60 mph ) = 40 mph 2 30 mph 2 hr = 60 miles ½ 10 m/s/s 5 2 = 125 m
2-5. Free Fall The acceleration of gravity (g) for objects in free fall at the earth's surface is 9.8 m/s 2. Galileo found that all things fall at the same rate.
2-5. Free Fall The rate of falling increases by 9.8 m/s every second. Height = ½ gt 2 For example: ½ (9.8 )1 2 = 4.9 m ½(9.8)2 2 = 19.6 m ½ (9.8)3 2 = 44.1 m ½ (9.8)4 2 = 78.4 m
2-5. Free Fall A ball thrown horizontally will fall at the same rate as a ball dropped directly.
2-5. Free Fall A ball thrown into the air will slow down, stop, and then begin to fall with the acceleration due to gravity. When it passes the thrower, it will be traveling at the same rate at which it was thrown.
2-5. Free Fall An object thrown upward at an angle to the ground follows a curved path called a parabola.
2-6. Air Resistance In air… –A stone falls faster than a feather Air resistance affects stone less In a vacuum –A stone and a feather will fall at the same speed.
2-6. Air Resistance Free Fall –A person in free fall reaches a terminal velocity of around 54 m/s –With a parachute, terminal velocity is only 6.3 m/s Allows a safe landing
2-6. Air Resistance Ideal angle for a projectile –In a vacuum, maximum distance is at an angle of 45 o –With air resistance (real world), angle is less Baseball will go furthest hit at an angle of around 40 o