As shown in the figure, 100 wooden blocks, each with weight 5 N, are clamped by two forces of magnitude F from the left and right. All contact surfaces have the same roughness. What is the friction force between block No. 27 and block No. 28?

It should be 250N - it's not hard for readers to verify on their own

yes

So, sir, do you already know the correct answer? Can you write down the process?？