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

GUSS Example 2

GUSS Example 2 Given: Using the quadratic formula: Or 1.8 s to 2 sig digs. Note that you want only the positive solution.

More Practice Textbook Questions: p. 10 #10, 12 p. 20 #5, 7