A theoms flask contains coffee. It is vigorously sheken, considering the coffee as the system. (a) Does its temperature rise ? (b) Has heat been added to it ? (c ) Has work been done on it ?

Explanation

Let's solve the problem step by step.

### Step 1: Determine if the temperature of the coffee rises when shaken.
When the coffee in the thermos flask is vigorously shaken, mechanical energy is transferred to the coffee. This mechanical energy increases the internal energy of the coffee. According to the kinetic theory of gases, an increase in internal energy typically results in an increase in temperature.

**Calculation:**
- The change in internal energy (ΔU) is related to the change in temperature (ΔT) by the equation:
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