To introduce Kinematics Definitions Displacement – time graphs Velocity – time graphs

Work for 20 / 9 / 16 Read the slides and copy out all the definitions for displacement, speed, instantaneous speed, average speed, acceleration and the displacement – time and velocity – time graphs. Complete the questions about the different graphs both in the presentation and from the worksheet ‘Graphs’.

Definitions Displacement is the distance moved by a body in a specified direction It is a vector quantity

Definitions continued Speed is the rate of change of distance It is a scalar quantity Units are ms-1 Instantaneous speed is the speed at any given instant On a car journey instantaneous speed is continually changing and it is shown on the speedometer reading Average speed = distance travelled time taken

Definitions continued Velocity is the rate of change of displacement of a body It is a vector quantity, so its value may be positive or negative depending on the direction of motion Units are ms-1 Velocity = change in displacement time taken

Definitions continued Acceleration is the rate of change of velocity of a body It is a vector quantity so its value may be positive or negative Acceleration = Change in velocity Time taken

Displacement time graphs Displacement (s) is plotted vertically against time (t) horizontally Gradient of a (s,t) graph = Velocity s s s s t t t t Copy out the sketch graphs and describe the motion in terms of velocity. Remember to include whether it is +ve or –ve What would be happening if the line was curved?

Velocity time graphs Velocity(v) is plotted vertically against time (t) horizontally Gradient of a (v,t) graph = acceleration Area under a (v,t) graph = distance travelled v v v v t t t t Copy out the sketch graphs and describe the motion in terms of acceleration. Remember to include whether it is +ve or –ve Describe the motion if the line was curved.

Copy out and draw the corresponding graphs?