Yes I realised that I missed the latent heat term in equation. But anyways included it in my calculations.
Also thanks for pointing out that the whole ice warms upto 0 deg C and not the 50-x thing. That was the source of my error. Thanks.
Since I don't know what the system will look like in the end I tried to check for the extreme cases.
Case 1 if the whole ice melts :
$$T_f = 170.5 K$$
Case 2 if the whole water freezes :
$$T_f = 291.33 K$$
Both of which are unreasonable. Therefore the mixture contains both water and ice, this...
Definitely, physics forum is a go to ! Especially when chatGPT doesn't correct my approach instead just gives solution. I expect Physics forum to help me identify what mistake in making so that I can correct my thought process.
Unfortunately the Examiner hasn't provided any solution, neither any standard textbooks have a similar problem as far as i know. so my only go to was ChatGPT. It gave the solution :
$$v(t) = \frac{\rho Au^{2}t}{M_{C}+\rho Aut}$$
in my solution there is ##M_{c}## which the the mass of container and ##M## which is shorthand for ##M(t)##. There could be a confusion between those two since the question mentions only ##M##. However now that i have mentioned my notations, i think it would be clear. There is time dependence...
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system
$$M(t) = M_{C} + m(t)$$
$$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$
$$P_i = Mv + u \, dm$$
$$P_f = (M + dm)(v + dv)$$
$$\Delta P = M \, dv + (v - u) \, dm$$
$$F =...