ENGR 2311: STATICS!
FALL 2015
Name: Quiz 09: Chapter 08
The uniform rod has a mass m = 10kg, and length L = 0.5m. It
is supported by the smooth (assume frictionless) ring at B. If,
at the 30° angle shown, the rod is on the verge of slipping,
determine the coefficient of static friction µs between the rod
and the floor at point A.
NB
mg
fA
NA
ENGR 2311: STATICS!
FALL 2015
The cylinder weighs 10 lb and is held in equilibrium by the belt and wall. If slipping does not
occur at the wall, determine the minimum vertical force P which must be applied to the belt for
equilibrium. The coefficient of static friction between the belt and the cylinder is µs = 0.25.
(HINT: T1 = P, and T2 = T1eµβ. Also, β must be in radians. Also, ΣMA = 0.)
30°
β = 30° = π/6 rad
fA
T2cos30°
T2
T2
T2sin30°
r(1+cos30°)
β=30°
r
T1
30°
2r
NA
W
T1
r
W
rsin30°
A