Question

1. Three identical uniform bricks of mass m and length L are stacked on top of each other. (a) What is the maximum distance d so that the stack does not tumble over? (Hint: consider the top two bricks first, then add the bottom brick) (b) What is the maximum distance d that can be achieved by optimal stacking of an infinite number of bricks?

Answer 1

Centre of gravity is the point through which net gravity force act on block 1 when c g is at the edge of block 2, block 1 is just about to rotate since when r = 1/2, c g matches with 2 edge of block 2 there is no moment as torque but if x > l/2 there will be torque hence, maximum extension will be r = 1/2 Now, if centre of gravity of combined block 1 and block 2 crosses the right edge of block 3, then there will be moment the combined c g of block 1 and 2 is d = (1/2 + l/2) = 31/4 if d > 3l/4. There will be torque hence, maximum extension will be d = 3l/4 (b) as block increases c g increases hence d rightarrow infinity for infinite no of bricks