PSLE
The graph shows the temperature of water in a pot from 1300 to 13 36.
- For how many minutes was the temperature of the water 60°C and below? Give your answer in min.
- During which two 6-minute intervals did the temperature of water decrease at the same rate? Give your answer in the following format. (Eg 01 00 to 01 15, 01 25 to 01 30)
- What was the change in temperature per minute from 1324 to 1330? Give your answer in °C/min.
(a)
Temperature of water that reached 55°C at 13 12.
From 13 06 to 13 36: 30 min
Duration that the temperature of water that reached 60°C and below = 30 min
(b)
Decrease in temperature of water
From 13 00 to 13 06: 71°C - 60°C = 11°C
From 13 6 to 13 12: 60°C - 55°C = 5°C
From 13 12 to 13 18: 55°C - 35°C = 20°C
From 13 18 to 13 24: 35°C - 21°C = 14°C
From 13 24 to 13 30: 21°C - 15°C =
6°C
From 13 30 to 13 36: 15°C - 9°C =
6°C
Two 6-minute intervals that the temperature of water decreas
es at the same rate are 13 18 to 13 24 and 13 24 to 13 30. (c)
Change in temperature per minute from 13 24 to 13 30
= 6 ÷ 6
= 1°C/min
Answer(s): (a) 30 min; (b) 13 18 to 13 24, 13 24 to 13 30; (c) 1°C/min