450.
The chain AB exerts a force of 20 lb on the door at B.
Determine the magnitude of the moment of this force along
the hinged axis x of the door.
z
3 ft
2 ft
A
SOLUTION
O
Position Vector and Force
28 CHAPTER 2 FORCE VECTORS
2—1. Determine the magnitude of the resultant force
FR = F1 + F2 and its direction, measured counterclockw1se
from the positive x axis.
r1 = 2501b
F2 = 3751b
Prob. 2—1 '
4138.
The loading on the bookshelf is distributed as shown.
Determine the magnitude of the equivalent resultant
location, measured from point O.
2 lb/ft
3.5 lb/ft
O
A
2.75 ft
4 ft
SOLUTION
+ TFR O = F
511.
Determine the magnitude of the reactions on the beam at A
and B. Neglect the thickness of the beam.
600 N
3
5
4
B
A
4m
SOLUTION
a + MA = 0;
By (12) - (400 cos 15)(12) - 600(4) = 0
By = 586.37 = 5
45.
Determine the moment about point B of each of the three
forces acting on the beam.
F2 = 500 lb
F1 = 375 lb
5
A
4
3
B
0.5 ft
8 ft
SOLUTION
F3 = 160 lb
Ans.
4
a +1MF22B = 500 a b 152
5
= 2000 lb # f
2—1.
Determine the magnitude ofthc rcsuilant force FR 2 Fl + F2
and its directiou, measured counterclockwise from the positive
x axis.
SOLUTION
FR : \/(250)2 + (375)2 — 2(250)(375) cos 750 = 393.2
393
l
94 CHAPTER 3 EQUILIBRIUM OF A PARTICLE 3.3 COPLANAR FORCE SYSTEMS 95 1
I
I F NleMEN'FAL "PliaBL‘EMS:
All oblem solutions must include an FBD F3—4. The block has a mass of 5 kg and rests on the smo
562.
The uniform load has a mass of 600 kg and is lifted using a
uniform 30-kg strongback beam and four wire ropes as
shown. Determine the tension in each segment of rope and
the force that must be ap
*628.
Determine the force in members CD, HI, and CJ of the truss,
and state if the members are in tension or compression.
J
K
I
H
G
4 ft
A
B
SOLUTION
3 ft
Method of Sections: The forces in members HI,
62.
Determine the force on each member of the truss and state
if the members are in tension or compression. Set
P1 = 500 lb and P2 = 100 lb.
6 ft
8 ft
C
A
8 ft
SOLUTION
Method of Joints: In this case,
2—89.
If F : {350i — 2503‘ 45014} N and cabie AB is 9 m long.
determine the x. y, z coordinates of point A.
SOLUTiON
Position Vector: The position vector 1313. directed from point A to point B. is giv
45.
Determine the moment about point B of each of the three
forces acting on the beam.
F2 = 500 lb
F1 = 375 lb
5
A
8 ft
SOLUTION
a +1MF12B = 3751112
0.5 ft
5 ft
F3 = 160 lb
Ans.
= 2000 lb # ft = 2.00
343.
Determine the magnitude and direction of the force P
required to keep the concurrent force system in
equilibrium.
z
(1.5 m, 3 m, 3 m)
P
F2 = 0.75 kN
120
SOLUTION
F3 = 0.5 kN
45
Cartesian Vector N