Presentation on theme: "Three featured concepts are: Speed Velocity Acceleration"— Presentation transcript:
1Three featured concepts are: Speed Velocity Acceleration MOTIONThree featured concepts are:SpeedVelocityAcceleration
2MATH CONNECTION These are called rates The units in Math may have been BELike Feet per second; Miles per hourFt./Sec OR mi./hr. or mph
3In Science we use SI UNITS Meters per second; kilometers per hourm/s OR km/h or kphThere are as may rates as there are units:cm/s; mm/h; even mm/y or cm/centuryIt all depends on the topic of study.
4What’s the dif? Glad you asked: Speed is a rate of distance over time or just called magnitude like:5 m/s or 25 mph.VOLOCITY is the rate of distance over time but indicates a direction! Magnitude + direction:5m/s -north or 25 mph-south
5So can you tell the difference? TRY SOME:15 m/s100 mph - north2.34 cm/s17.4 ft./hr.-up25 kph- south11.67 km/h
6How about Acceleration? Acceleration is defined as a change in speed of velocity over time. More complicated for sure.a =∆v / ∆tWe have to check out the white board to see this broken down!!!!
7UNITS for ACCELERATION Because it involves a double division the units of course are complicated usinfg two speeds together.Examples of acceleration units are:m/s/s (not new) remember 9.8 m/s/s? or m/s2Ft./sec./sec or ft./sec.2Km/h/sm/h/sBasically any distance divided by a time divided by another time:anyd/t/t defines an acceleration unit of measure!
8Sample Speed Problem #1It takes a car 30 seconds to go 90 meters. What is the speed?Menu: V = d/t (means d ÷ t)V= ? = 90m/ 30sd = 90 m V = 3m/st = 30 s
9PROBLEM # 2A car can travel a speed of 3 m/s over a time of 30 seconds how far would it go?Menu: d = vt (means v X t)d = ? = (3 m/s) (30 s) (cross cancel s)v = 3 m/s d = 90 mt = 30 s
10PROBLEM # 3How long will it take a car to go 90 meters at a speed of 3 m/s?Menu: t = d/v ( means d ÷ v )t = ? = 90 m / 3m/sd = 90 m [t= 30 s]v = 3 m/s
11ACCELERATION Sample Problem: A car’s speedometer indicates a speed of 30 kph and after 10 seconds of time the driver notices the speed is now 90 kph.What is the car’s acceleration?a = ? a = vf - vitvf = 90 km/h = 90 km/h - 30 km/h10 svi = 30 km/h = km/ht= 10 s a = 6 km/h/s
12Deceleration a= ? a = Vf - Vi t Vf = 55 kph = 55 kph – 75 kph 5s Sample Problem:A truck is going 75 kph and 5 seconds later it is clocked going 55 kph. What is the deceleration.HINT: Use the same equation (formula) then change the a to (–a) after finding the answer.a= ? a = Vf - VitVf = 55 kph = 55 kph – 75 kph5sVi = 75 kph = kpht = 5s a = -4kph/s-a = 4 kph/s