Average Velocity Speed versus Velocity Speed v The

Average Velocity

Speed versus Velocity Speed (v): The distance an object travels during a given time interval. Does not include distance (Scalar) -eg 100 km/h Velocity (v): The displacement of an object during a given time interval -eg 100 km/h [N]

Speed versus Velocity Same speed different velocity Note: Speed is the same

Speed versus Velocity Same speed different velocity Note: Speed is the same velocity is different (+, -)

Velocity and Displacement: Velocity always travels in the same direction as displacement. SI units = m/s

Calculating Velocity using Slope Velocity = Slope of a position time graph Slope = Δd = (df - di) Δt (tf - ti)

Example: Slope = Δd = (df - di) = (60 m - 0 m) = Δt (tf - ti) (10 s – 0 s)

. Slope = Δd = (df - di) = (60 m - 0 m) = 60 m = 6 m/s Δt (tf - ti) (10 s – 0 s) 10 s

. Slope = Δd= (df - di) = (-40 m - 60 m) = Δt (tf - ti) (40 s – 15 s)

. Slope = Δd= (df - di) = (-40 m - 60 m) = -100 m = -4 m/s Δt (tf - ti) (40 s – 15 s) 25 s

. Slope = Δd= (df - di) = (0 m - -40 m) = 40 m = 2. 7 m/s Δt (tf - ti) (55 s – 40 s) 15 s

Try calculating the velocity for the other two slopes Remember the slope can be either positive negative or zero

Average Velocity (Vav): Because it is almost impossible for something to move in perfect uniform velocity we usually take the average of the velocities in a time interval. Eg, Using a best fit line

Converting m/s to km/h Parts: 1 h = 3600 s 1 km [W] = 1000 m [W] Convert 7200 s to hours Convert 3 hour to seconds

Converting m/s to km/h Parts: 1 h = 3600 s 1 km [W] = 1000 m [W] Convert 600 s to hours 7200 s X 1 h = 2 h 3600 s Convert 3 hour to seconds

Converting m/s to km/h Parts: 1 h = 3600 s 1 km [W] = 1000 m [W] Convert 600 s to hours 7200 s X 1 h = 2 h 3600 s Convert 3 hour to seconds 3 h X 3600 s = 10 800 s 1 h

. Converting 6 km to m 6 km X 1000 m = 6000 m 1 km Convert 27000 m to km

. Converting 6 km to m 6 km X 1000 m = 6000 m 1 km Convert 27000 m to km 27000 m X 1 km = 27 km 1000 m

Converting m/s and km/h Eg. 55 km/h 55 km x (1000 m) x 1 h = 15 m/s 1 h 1 km 3600 s Hi Ms. Krom!!