A horizontal force `F` is applied to a homogeneous rectangular block of mass `m`, width `b` and height `H`. The block moves with constant velocity, the coefficient of friction is `mu_(k)`.
a. What is the greater height `h` at which the force `F` can be applied so that the block will slide without tipping over ?

b. Through which point on the bottom face of the block will the resultant of the friction and normal forces act if `h=H//2?`
c. If the block is at rest and coefficient of static friction is `mu_(s)` what are the various criteria for which sliding or tipping occurs?