FYKOS Year 29 Series 4 Problem 5 — Slide · FYKOS 29 #29.4.5
Physics · mechanics · thermodynamics
Problem
There are two identical blocks with the mass m and one of the sides of lenght lon a horizontal plane. The distance between the closest two faces is 2x0. Suddenly we start pouring water between them with the volume flow Q. At two sides of the blocks there is a barrier keeping the water in the place between the two blocks. The coefficient of static friction between the block and the plane is f0 and the of the kinetic friction is f. There is no friction between the barriers and the blocks. What is the condition for f0 that would keep the blocks in place? In the case of sufficiently small f0, determine the acceleration of blocks as a function of position and also the distance, where the blocks eventually stop moving. Consider all the movement of the water reasonably slow, for any eddies to appear, for any heating of the water solely from its movement to take place or for any significant kinetic energy possesion. For the same reason of very slow Q, we can approximate there is no contribution of adding any water past the point where the blocks started moving. Bonus: Find a condition for turning the block over.