So this idea came from a post I made in SRK. I personally love doing this kind of stuff, it’s one of my favorite pastimes (and I’m hoping I’m not the only one). I figured we could post some problems/brainteasers and see what sort of solutions the people from SRK come up with. I was also thinking people could even maybe post some schoolwork problems within reason (if you are doing a thesis on Galois Theory then maybe this isn’t the best place to come for assistance). If this thread ends up being a bust then so be it, but it’s worth a shot as this stuff can be really fun. One thing I would ask is that if you post a problem/solution that you didn’t write, then mention that you didn’t write it (don’t plagiarize). So to kick it off I’ll post two problems, one easy and one difficult, neither of which were written by me, although I’ll post my solutions in time:

The easy:

If exactly one of these statements is false, which statement is false?

A) Statement D is true

B ) Statement A is false

C-x) Statement B is false

D) Statement C-x is true

Apologies for the somewhat weird notation; I had to do that in order to avoid getting emoji. Problem written by Sandeep Bhardwaj

The hard:

A toilet paper roll of mass **m = 150g** with inner radius **r = 1.5cm** and outer radius **R = 5cm** is put on a small cylindrical bar with coefficient of friction **k = 2** . If we pull the paper straight down very slowly and increase the force very gradually, the inner part of the roll will first move without slipping on the bar. Then at some critical force **F_c** , it will start to slip. Assume that the pulled out piece of paper is always vertical. Find **F_c** in Newtons. Assume that ** g = -9.8 m/s^2** Problem written by David Mattingly.