1 Chapter 2 Motion 2-1. Speed 2-2. Vectors 2-3. Acceleration 2-4. Distance, Time, and Acceleration Free Fall System 2-6. Air Resistance 2-7. First Law of Motion2-8. Mass2-9. Second Law of Motion2-10. Mass and Weight2-11. Third Law of Motion2-12. Circular Motion2-13. Newton's Law of Gravity2-14. Artificial Satellites
2 2-1. Speed Definitions: v = d/t Speed General formula for speed: The rate at which something moves a given distance.Faster speeds = greater distancesGeneral formula for speed:Speed = distance / timeAbbreviations commonly used:d = distance t = time v = speedv = d/t
9 2-5. Free FallThe acceleration of gravity (g) for objects in free fall at the earth's surface is 9.8 m/s2.Galileo found that all things fall at the same rate.
10 2-5. Free Fall The rate of falling increases by 9.8 m/s every second. Height = ½ gt2For example:½ (9.8 )12 = 4.9 m ½(9.8)22 = 19.6 m½ (9.8)32 = 44.1 m½ (9.8)42 = 78.4 m
11 2-5. Free FallA ball thrown horizontally will fall at the same rate as a ball dropped directly.
12 2-5. Free FallA 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.
13 2-5. Free FallAn object thrown upward at an angle to the ground follows a curved path called a parabola.
14 2-6. Air Resistance In air… In a vacuum A stone falls faster than a featherAir resistance affects stone lessIn a vacuumA stone and a feather will fall at the same speed.
15 2-6. Air Resistance Free Fall A person in free fall reaches a terminal velocity of around 54 m/sWith a parachute, terminal velocity is only 6.3 m/sAllows a safe landing
16 2-6. Air Resistance Ideal angle for a projectile In a vacuum, maximum distance is at an angle of 45oWith air resistance (real world), angle is lessBaseball will go furthest hit at an angle of around 40o