Solving Motion Word Solving Motion Word ProblemsProblems

You NEED to know how to You NEED to know how to use these equations use these equations

(they will be given on assessments)(they will be given on assessments) Speed = d Speed = d ÷ t÷ t Distance = s x tDistance = s x t Time = d ÷ sTime = d ÷ s Velocity = d ÷ tVelocity = d ÷ t Displacement = v x tDisplacement = v x t Time = d ÷ vTime = d ÷ v Acceleration = ∆v ÷Acceleration = ∆v ÷ t VelocityVelocity = a x t= a x t Time = Time = ∆∆v v ÷ a÷ a

Steps when solving word Steps when solving word problemsproblems

1.1. Write down what you are given in the Write down what you are given in the question and what you are asked to question and what you are asked to find. find.

2.2. Write down the equation you will use. Write down the equation you will use.

3.3. Plug in what numbers you know.Plug in what numbers you know.

4.4. Solve, and include the proper units. Solve, and include the proper units.

5.5. Check your work Check your work

Interpreting Word ProblemsInterpreting Word Problems TimeTime Units: seconds, minutes, hoursUnits: seconds, minutes, hoursExamples: the trip took 3 minutes; he traveled for 5 Examples: the trip took 3 minutes; he traveled for 5

hours; it took 45 secondshours; it took 45 seconds DistanceDistanceUnits: metres, kilometersUnits: metres, kilometersExamples: she went/traveled/ran/drove/flew/biked Examples: she went/traveled/ran/drove/flew/biked

30 metres30 metres SpeedSpeedUnits: m/s, km/hUnits: m/s, km/hWords: the car was going 100km/h; the balloon rose Words: the car was going 100km/h; the balloon rose

at a speed of 10m/sat a speed of 10m/s AccelerationAccelerationUnits: m/sUnits: m/s22

Words: the car accelerated 2m/sWords: the car accelerated 2m/s22; the bike slowed ; the bike slowed down at a rate of -6m/sdown at a rate of -6m/s22

Example #1Example #1 High speed elevators can go 7.11m/s. High speed elevators can go 7.11m/s.

How much time would they need to How much time would they need to go up 37.5m?go up 37.5m?

Speed = 7.11 m/sSpeed = 7.11 m/s

Distance = 37.5 mDistance = 37.5 m

Time = ?Time = ?

Time = distance ÷ speedTime = distance ÷ speed

Time = 37.5 m ÷ 7.11 m/sTime = 37.5 m ÷ 7.11 m/s

Time = 5.27 secondsTime = 5.27 seconds

Example #2Example #2 Megan was biking at a velocity of +5m/s. Megan was biking at a velocity of +5m/s.

Then, she slowed down to a velocity of Then, she slowed down to a velocity of +2m/s in 25 seconds. What was her +2m/s in 25 seconds. What was her acceleration?acceleration?

Vinitial = +5m/s & Vfinal = +2m/sVinitial = +5m/s & Vfinal = +2m/s

SO SO ∆V = +2m/s - +5m/s; ∆V = -3m/s∆V = +2m/s - +5m/s; ∆V = -3m/s

Time = 25 secondsTime = 25 seconds Acceleration = ∆v ÷ tAcceleration = ∆v ÷ t A = -3m/s ÷ 25sA = -3m/s ÷ 25s A = -0.12 m/sA = -0.12 m/s22