U14 - compound measures using graphs

1tonne = ?kg

1000

5miles = ?km

8

speed =

distance/ time

pressure =

force/ area

rate of flow

quantity/ time

how to calculate the instantaneous rate of change of a curve

draw a tangent to the point you want to find the instantaneous rate of change of

calculate m of the tangent

there is a time (seconds)/ temperature (degrees Celcius) graph of water in a kettle

the gradient of the line is 2

what is an interpretation of the gradient

the temperature increases by 2C per second

how to approximate the area under a curve

• divide the curve into the specified number to make trapeziums

• calculate the area of each trapezium

• add them up

what does a straight line mean on distance/ time

moving at a constant speed

what does a horizontal line mean on distance/ time

stopped

what does a diagonal, straight line going up mean on distance/ time

moving at a constant speed

what does a diagonal, straight line going down mean on distance/ time

returning back to original position at a constant speed

what does area under the line equal on a velocity/ time graph

distance travelled

what does a positive gradient mean on a velocity/ time graph

acceleration

what does a negative gradient mean on a velocity/ time graph

decelerating

what does a flat line equal on a velocity/ time graph

moving at a constant speed