Speed Pages 220 223 Speed v Speed v
- Slides: 14
Speed Pages 220 – 223
Speed (v) • Speed, v, is the distance an object moves in a certain length of time • It is a scalar quantity meaning it has only magnitude (size) and is represented by a number and units • The most common units for speed are m/s and km/h
Graphically • Speed is found by the slope of a distance-time graph • Remember that slope is found by the formula
Average vs. Instantaneous • As an object moves, it often undergoes changes in speed. Therefore, we sometimes use different terms to describe speed of an object during movement. • Average Speed (vave) is the total distance an object travels divided by the time it takes to travel that distance
• Instantaneous Speed (vinst) is the speed of an object at a specific instant in time • It is found by the distance of the object at that instant divided by the time • Can you think of a real life example of average vs. instantaneous speed?
Constant & Changing Speed • Constant speed occurs when an object travels the same distance for each time interval • Changing speed occurs when an object travels a different distance for each time interval
Velocit y Pages 228 – 230
Velocity • Velocity describes the change in an objects position over time • It is a vector quantity meaning it describes magnitude (size) and direction and is represented with a number, units and a direction • The units for velocity are the same as those seen with speed: km/h and m/s
Graphically • The slope of a position-time graph is velocity
Average vs. Instantaneous • Average velocity is the displacement of an object divided by the time interval it takes to travel that displacement
• Instantaneous velocity is the velocity of an object at a specific instant in time. • It is found by the position of the object at that instant divided by the time
Constant & Changing Velocity • Constant velocity occurs when an object travels the same speed and same direction for each time interval • Changing velocity occurs when an object’s speed or direction, or both speed and direction change for each time interval
Practice Problems • Page 227 #’s 4, 5 abc, 10, 11, 13, 14 • Page 231 #’s 2, 3, 4, 5, 6, 14, 15, 16
