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## A Review of Kinematics

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**A Review of Kinematics**SPH4U http://www.youtube.com/watch?v=9YUtFpLpGfk**Distance and Displacement**For an object in motion, the distance travelled is the length of the path; the displacement is change in position.**Distance and Displacement**For an object in motion, the distance travelled is the length of the path; the displacement is change in position. Displacement is a vector quantity: direction matters! Ex.**Vectors in Equations**When substituting vector quantities into equations, direction is often indicated by a sign:**Vectors in Equations**When substituting vector quantities into equations, direction is often indicated by a sign: If a question also contains [up] and [down], horizontal and vertical components are considered separately.**Speed and Velocity**The rate at which an object is changing position is its velocity (also a vector quantity). Displacement Time interval Average velocity**Speed and Velocity**The rate at which an object is changing position is its velocity (also a vector quantity). Initial velocity Final velocity**Speed and Velocity**The rate at which an object is changing position is its velocity (also a vector quantity). (The units of velocity are m/s.)**Speed and Velocity**The rate at which an object is changing position is its velocity (also a vector quantity). The magnitude of the instantaneous velocity is the object’s speed.**Acceleration**The rate at which an object is changing velocity is the acceleration (also a vector quantity).**Acceleration**The rate at which an object’s velocity is changing is the acceleration (also a vector quantity). (The units of acceleration of m/s/s or m/s2.)**Kinematics Equations**These equations may be rearranged: Ex.**Kinematics Equations**And they may be combined to derive other equations with different combinations of variables:**GUSS**When problem solving, select the kinematics equation that contains your Givens and Unknown (and only these variables).**GUSS Example 1**How long does it take Usain Bolt to run 10.0 m, assuming he is starting from rest and is accelerating at 6.6 m/s2 [fwd]?**GUSS Example 1**How long does it take Usain Bolt to run 10.0 m, assuming he is starting from rest and is accelerating at 6.6 m/s2 [fwd]?**GUSS Example 1**How long does it take Usain Bolt to run 10.0 m, assuming he is starting from rest and is accelerating at 6.6 m/s2 [fwd]?**GUSS Example 2**For an object in free fall, How long will it take an Olympic diver with an initial velocity of 3.1 m/s [up] to hit the water 10.0 m below?**GUSS Example 2**Given: Using the quadratic formula: Or 1.8 s to 2 sig digs. Note that you want only the positive solution.