PSLE
The graph shows the temperature of water in a pot from 1000 to 10 36.
- For how many minutes was the temperature of the water 50°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 1030 to 1036? Give your answer in °C/min.
(a)
Temperature of water that reached 50°C at 10 12.
From 10 12 to 10 36: 24 min
Duration that the temperature of water that reached 50°C and below = 24 min
(b)
Decrease in temperature of water
From 10 00 to 10 06: 73°C - 57°C = 16°C
From 10 6 to 10 12: 57°C - 50°C = 7°C
From 10 12 to 10 18: 50°C - 33°C = 17°C
From 10 18 to 10 24: 33°C - 28°C =
5°C
From 10 24 to 10 30: 28°C - 9°C = 19°C
From 10 30 to 10 36: 9°C - 4°C =
5°C
Two 6-minute intervals that the temperature of water decreas
es at the same rate are 10 18 to 10 24 and 10 30 to 10 24. (c)
Change in temperature per minute from 10 30 to 10 36
= 9 ÷ 6
= 1.5°C/min
Answer(s): (a) 24 min; (b) 10 18 to 10 24, 10 18 to 10 24; (c) 1.5°C/min