Answer:
0.37 kg
Explanation:
I'm not a professor myself, but this is how I worked it out:
using the graph, after 100 seconds, the temperature is 100 degrees Celsius.
If we now substitute everything into the specific heat capacity equation, making the mass "m", we would come up with:
4200 = 155000/(m x 100)
If we rearrange and solve for m, we get 0.37 kg.
I'm not sure if I have done this correctly, feel free to correct me.
Hope this helps!