Question

Consider a uniform cubical box of side a on a rough floor that is to be moved by applying minimum possible force F at a point b above its centre of mass (see figure). If the coefficient of friction is μ = 0.4, the maximum possible value of 100 × (b/a) for a box not to topple before moving is ______ .

Answer 1

F = µmg ...(1)

0.8b + 0.4a = a

0.8 b = 0.6 a

b/a = 3/4

Answer 2

For no toppling 

b ≤ 0.75a (in limiting case)

But it is not possible as b can maximum be equal to 0.5a

(100/(b/a))_max = 50