9.19: calculate rate changes

Calculate the rate of decomposition

Rate of decomposition = change in value (such as mass)/change in time

Calculate the rate of decomposition of compost weighing 45 kg at the start and 33.7kg after 14 hours

45-33.7=11.3

11.3/14=0.807 kg/hour

The mass decreased, so the rate of change should be negative = -0.807 kg/hour

How can rate of change be calculated from graphs?

Calculate the gradient

Rate of change=vertical change/horizontal change

Calculate the rate of change using this graph

6.6-5.4=1.2

50-0=50

1.2/50=0.024

As the gradient is negative, the rate of change should be negative too = -0.024