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Unit 3 Slideshow 2 Motion is a measure of CHANGES IN POSITION, as marked by HOW FAR, HOW LONG, and HOW FAST an object travels.
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FASTEST PRODUCTION CAR LINKLINK FASTEST LAND MAMMAL LINKLINK FASTEST WING SPEED LINKLINK FASTEST ANIMALS SLOWED DOWN LINKLINK FASTEST RUBIX CUBE LINKLINK FASTEST HANDS LINKLINK FASTEST EVERYTHING LINKLINK
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SCALAR VS. VECTOR SCALAR QUANTITIES DISTANCE TYPES OF SPEED SPEED CALCULATIONS DISTANCE-TIME GRAPHS SPEED-TIME GRAPHS
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SCALAR QUANTITIES Any quantity that has MAGNITUDE (size) and UNITS, but NO DIRECTION. EXAMPLES: ▪ Time2.5 h ▪ Speed 25 m/s ▪ Mass5.0 kg ▪ Distance42 m
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VECTOR QUANTITIES Any quantity that has MAGNITUDE (size) and UNITS, and DIRECTION. Direction is symbolized by putting an ARROW above the symbol for a quantity. ▪ Ex: velocity has the symbol v EXAMPLES: ▪ Velocity 25 m/s [R] ▪ Weight50 N [D] ▪ Displacement42 m [W33 o N]
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CONSTANT SPEED (Δv) AKA UNIFORM MOTION When an object is travelling at constant speed, it is travelling at the SAME SPEED for a period of time. EXAMPLE ▪ Cruise control ▪ Speed of light in air is c = 3.00 x 10 8 m/s
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AVERAGE SPEED (v av ) A measure of the TOTAL distance over TOTAL time. V av = d TOTAL = d T t TOTAL = t T INSTANTANEOUS SPEED (v inst ) A measure of the speed at a particular MOMENT in time. Instantaneous speed is NOT affected by an object’s PREVIOUS SPEED or HOW LONG is has been moving. EXAMPLE: ▪ Speedometer ▪ Police Radar Gun
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When doing physics problems, follow the following guidelines: READ PROBLEM (i.e., don’t just pick out the numbers)! Write GIVENS and UNKNOWNS. Write EQUATION FIRST, rearranging if necessary. Plug in numbers and solve for answer. Write answer in SIG FIGS, with UNITS, and CIRCLE it!
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Since the SPEED equation has only 3 VARIABLES, you can easily rearrange it using the following helpful “triangle.” Χ ÷ Δv = ? Δd = ? Δt = ?
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_____________ wants to ride his bike from Corner Brook to Deer Lake, a distance of 45 km. If he only has 0.50 h to get there, what speed does he have to travel?
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_____________ wants to ride her bike from Corner Brook to Deer Lake, a distance of 45 km. Unlike ____________, she calculated her average speed to be 20.0 km/h. How long will it take her to get there?
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______________ is travelling for a triathlon and ran at a speed of 15 km/h for 2.0 h. What distance has he travelled?
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On her scooter, ______________ travels 12 km in 2.5 h and then 15 km in 35.5 minutes. What is her average speed?
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Do the Worksheets 7 and 8 (page 20-21)in your handout for homework!!!
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the truck? v car = 90 km/h = 25 m/s v truck = 50 km/h = 14 m/s d = 100 m t for car to reach truck = ? d truck + 100 = d car vt + 100 = vt 14t + 100 = 25t 100 = 11t 9 = t t= 9 s
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