Homework No. 9
(1) The T-shaped bar is loaded with two forces and a
moment as shown. The bar is supported by a pin at O
and a roller at C. The mass of the bar is negligible. (a)
For P = 100 N, determine the normal force at roller C
and the magnitude of the reaction at pin O. (b)
Determine the maximum load Pmax that can be applied
for the T-shaped bar to maintain equilibrium.
Ans: (a) NC = 240 N, O = 116.6 N (b) Pmax = 260 N
(2) The 100 lb uniform bar is pinned at O and
supported by a roller at A. A downward 150 lb force
and a moment M are applied at its lower end as shown.
(a) If M = 2000 lb-in, determine the magnitude of the
reaction force at pin O. (b) Determine the maximum
moment Mmax for the bar to be in static equilibrium.
Ans: (a) 522 lb (b) 5000 lb-in
(3) A 900 N force is applied to the bracket
that is pinned at C and constrained by the
fixed pin in the smooth slot at B. Determine
the magnitude of the reaction at pin C.
Ans: C = 2.29 kN
(4) The uniform disk weighs 12 lb with a radius of 4 ft, and it
is supported as shown by a smooth vertical wall B and a rough
inclined wall A. A 60 lb block is mounted on the disk at the
midpoint between the center C and wall B. If the disk does not
slip and remains in equilibrium, determine the friction force on
wall A and the normal forces from walls A and B.
Ans: NB = 146 lb, NA = 160 lb, FA = 30 lb
(5) The two pulleys are fastened together to form an
integrated unit, and they are prevented from turning
about the bearing support O by a cable wound securely
around the smaller pulley and fastened to point A.
Determine the magnitude of the reaction at the bearing
when a downward force of 2 kN is applied as shown.
Neglect the weight of the pulleys.
Ans: O = 4.38 kN
(6) The 120 lb boy standing on the 200 lb uniform beam
exerts a pull of 40 lb on the rope rigged as shown.
Compute the magnitude of the reaction at the pinned
support O.
Ans: O = 820 lb
(7) Three loads are applied to the cantilever
beam shown. Determine the reactions at the
fixed support O.
Ans: Ox = 0.7 kN ←, Oy = 4.21 kN ↑,
MO = 5.99 kN·m CCW
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