6/10 A vehicle tire exerts the force $P$ on the tire chock.
(a) Determine the minimum coefficient of static friction common to both $A$ and $B$ so that the chock will not slip relative to the horizontal support surface.
(b) If foot $A$ rests on an oily spot for which the coefficient of static friction is essentially zero, determine the minimum friction coefficient at foot $B$ for static equilibrium. State any assumptions.
$P$
$38^\circ$
$A$
$46$ mm
$B$
$64$ mm
$58$ mm