Chapter 8 Lesson 4 Speed Velocity How do
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Chapter 8 Lesson 4 Speed & Velocity • How do you calculate speed? • How do you describe velocity? • How do you graph motion?
The distance an object travels/moves in a unit of time; a type of “rate”. Speed
• To calculate the speed of an object, divide the distance the object travels by the amount of time it takes to travel that distance: • Speed= Distance Time The Speed Equation
Average Speed Divide total distance traveled by the total time: Distance ÷ Time
AVERAGE SPEED Use the data in the boxes below to calculate each triathlete’s average speed during the swimming and biking legs of the race (p. 308)
3. 0 km + 50. 0 km + 12. 0 km = 65. 0 km 0. 8 h + 3. 0 h + 1. 2 h = 5. 0 h 65. 0 km/5. 0 h = 13 km/h 1. 0 h + 2. 5 h + 1. 0 h = 4. 5 h 65. 0 km/4. 5 h = 14. 4 km/h Triathlete B
Instantaneous Speed the speed of an object at a given time
divide the distance by the time. instantaneous
Velocity An object’s speed & direction An error in determining velocity, either in speed or in direction, could lead to a collision
The pilots need to control both speed and direction, or velocity, to fly in formation.
velocity
1, 000 m west and 600 m south Total distance = 1600 m (1, 000 + 600 m) Total time = 300 s (5 min x 60 s) Average speed = 5. 3 m/s (1600/300 s) …by the distance it travels and its average speed and direction of the object’s motion.
How Do You Graph Motion? • With a line graph • Plot distance verses time
Distance verse time graph: • X-axis-horizontal line/independent variable • Always has time plotted on it! • Y axis- vertical line/ dependent variable
Slope • The steepness of a line on a line graph
What does a slope show? • The rate of change in speed • The steeper the slope is, the greater the speed
0 m 1 min 0 m/min 150 m 1 min 150 m/min 200 m 1 min 200 m/min slope Slope = 900 m/3 min = 300 m/min No; the object would have to cover distance in no time.
1. How do you calculate speed? Review 2. How do you describe velocity? 3. How do you graph motion? Speed= Distance ÷ Time With speed & direction Time is on the x axis & distance is on the y axis