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Unformatted text preview: an experimentalist, performed many experiments with falling objects from the Leaning Tower of Pisa. Through these experiments, he conclusively refuted Aristotle’s concept of motion. Galileo realized that time was an important factor in describing motion. He studied change of various quant ities with t ime, and introduced concept of rate to the study of motion. 4 Physical Science 1 Chapter 2 SPEED
· Speed is the rate of change of distance with time. speed= distance
d s= time
t Total distance Average speed ( s)= Total time
· Instantaneous speed is speed at a given time. Examples: 1. Determine the speed (km/h) of a biker who travels 10 km in 12 minutes. d
10 km 60 min s = = x = 50 km/h t
12 min 1 h 2. Sound travels at about 340 m/s. 5.0 seconds after seeing the lightning in a cloud, you hear thunder. How far away is the cloud? m d = s x t = 340 x 5.0 s =1700 m or 1.7 km s 3. Mary jogs 1.5 miles fro m her ho me to the track in 20 min, and returns ho me in 25 min. What is Mary’s average speed ( mi/h) for the ent ire distance? s = total distance
1.5 mi+1.5 mi 60 min = x =4.0 mi/h total time
20 min +25 min 1 h 4. A racecar travels 180 km in 72 minutes. What is the speed of the racecar in km/h? 5 Physical Science 1 Chapter 2 VELOCITY
· Velocity is speed in a particular direction (vector quant...
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This document was uploaded on 03/18/2014 for the course CHEM 322 at Los Angeles Mission College.
- Spring '14