IGCSE PHYSICS MOTION LESSON PLAN
1. Speed definition
a. Distance travelled per unit time
∆s
b. v=
∆t
c. Speed is a scalar quantity
2. Velocity definition
a. Speed towards a given direction
b. Velocity is a vector quantity
3. Average speed formula
total distance travelled
a. average speed=
total timetaken
4. Acceleration definition and formula
a. Rate of change of speed or change of velocity per unit time
∆v
b. a=
∆t
5. Distance/speed-time graphs
Distance-time Speed-time
x-axis Time Time
y-axis Distance/position Speed/velocity
The gradient Shows speed Shows acceleration
Straight line graph Constant speed Constant acceleration
Curved line graph Changing speed Changing acceleration
Horizontal line graph At rest; 0 speed Constant speed, 0
acceleration
Area under curve - Shows distance travelled
Acceleration Curved increasing graph Increasing graph/positive
gradient
Maximum acceleration Steepest gradient
Deceleration Curved decreasing graph Decreasing graph/negative
gradient
6. Speed calculations from s(t) graphs
a. Limited to straight line graphs
b. Find two points on the graph, (x1;y1) and (x2;y2)
y 2− y1
c. speed=m=
x 2−x 1
7. Acceleration calculations from v(t) graphs
a. Limited to straight line graphs
b. Find two points on the graph, (x1;y1) and (x2;y2)
y 2− y1
c. speed=m=
x 2−x 1
8. Distance calculations from v(t) graphs
a. Limited to straight line v(t) graphs
b. Divide the v(t) graph into common shapes
c. Use known area equations to find the distance
1
i. A ( ∆ )= bh
2
ii. A ( rectangl e )=lb
1
iii. A ( trapezium )= ( a+b ) h
2
d. Add up all areas under v(t) to get the total distance travelled.
