(a) To find the value of f(−15,60), we need to look up the value in the given table where the temperature T is −15 and the wind speed v is 60. This value represents the wind-chill index, which indicates how cold it feels at that temperature and wind speed.
(b) The question asks for the wind speed v that results in a wind-chill index of −30 when the temperature is −20. We need to find the value of v in the table where f(−20,v)=−30.
(c) The question asks for the temperature T that results in a wind-chill index of −43 when the wind speed is 20. We need to find the value of T in the table where f(T,20)=−43.
To find the value of f(−15,60), we look up the table where the temperature T=−15 and the wind speed v=60. The table provides the wind-chill index for these conditions.
The value f(−15,60)=−30 means that when the actual temperature is −15∘C and the wind speed is 60km/h, the air feels like −30∘C without wind.
We need to find the wind speed v such that f(−20,v)=−30. From the table, when T=−20, the wind speed v=60 results in a wind-chill index of −30.
This means that when the temperature is −20∘C, a wind speed of 60km/h makes the air feel like −30∘C.
We need to find the temperature T such that f(T,20)=−43. However, the table does not provide a value for T that satisfies this condition, as indicated by the result T=None.
- f(−15,60)=−30
- v for f(−20,v)=−30 is 60km/h
- T for f(T,20)=−43 is None (no such temperature exists in the table)