2.3-2.4 FoS PPT.pdf

Units of Measurement What is the label when we measure speed? miles per hour = m/h or mph kilometers per hour = km/h feet per second = ft/s meters per second = m/s Velocity the speed AND direction of an object Application… Polar bears are extremely good swimmers. If a polar b...

Units of Measurement What is the label when we measure speed? miles per hour = m/h or mph kilometers per hour = km/h feet per second = ft/s meters per second = m/s Velocity the speed AND direction of an object Application… Polar bears are extremely good swimmers. If a polar bear is swimming at an average of 2.6 m/s, how far will it have traveled after 120 seconds? Vector Quantity – specifies direction as well as magnitude. All the Constants Constant speed – steady speed (does not speed up or slow down) Constant direction – a straight line (the object’s path doesn’t curve) ergo we can have… Constant velocity – both constant speed and constant direction Concept Check What is the difference between speed and velocity? Speed is distance over time. Velocity includes direction. Concept Check What is the average speed of a cheetah that sprints 100 m in 4 seconds? 25 m/s How about if it sprints 50 m in 2 seconds? 25 m/s Concept Check The speedometer on a bicycle moving east reads 50 km/h. It passes a bicycle moving west at 50 km/h. Do both bikes have the same speed? YES Do they have the same velocity? NO Motion Is Relative Section 2.4 Motion is Relative Relative Motion motion that is relative to something else A space shuttle moves at 30,000 kilometers per hour. By this, we mean relative to Earth below. Relative to the sun? Train example… Quick Recap… Aristotle used logic to establish his ideas of motion. Galileo used experiments. The way was paved for…