Download - Exam 3 Concept Qs Super Important to Print
READING QUIZ
1. One of the assumptions used when analyzing a simple truss is that
the members are joined together by __________.
A) Welding B) Bolting C) Riveting
D) Smooth pins E) Super glue
2. When using the method of joints, typically _________ equations of
equilibrium are applied at every joint.
A) Two B) Three
C) Four D) Six
CONCEPT QUIZ
1. Truss ABC is changed by decreasing its
height from H to 0.9 H. Width W and load
P are kept the same. Which one of the
following statements is true for the revised
truss as compared to the original truss?
A) Force in all its members have decreased.
B) Force in all its members have increased.
C) Force in all its members have remained
the same.
D) None of the above.
H
P
A
B C
W
CONCEPT QUIZ
(continued)
2. For this truss, determine the number of zero-force
members.
A) 0 B) 1 C) 2
D) 3 E) 4
F F
F
ATTENTION QUIZ
1. Using this FBD, you find that FBC = – 500 N.
Member BC must be in __________.
A) Tension
B) Compression
C) Cannot be determined
2. For the same magnitude of force to be
carried, truss members in compression
are generally made _______ as compared
to members in tension.
A) Thicker
B) Thinner
C) The same size
FBD
FBC
B
BY
READING QUIZ
1. In the method of sections, generally a “cut” passes through no
more than _____ members in which the forces are unknown.
A) 1 B) 2
C) 3 D) 4
2. If a simple truss member carries a tensile force of T along its
length, then the internal force in the member is ______ .
A) Tensile with magnitude of T/2
B) Compressive with magnitude of T/2
C) Compressive with magnitude of T
D) Tensile with magnitude of T
CONCEPT QUIZ
1. Can you determine the force in
member ED by making the cut
at section a-a? Explain your
answer.
A) No, there are 4 unknowns.
B) Yes, using MD = 0 .
C) Yes, using ME = 0 .
D) Yes, using MB = 0 .
CONCEPT QUIZ
2. If you know FED, how will you determine FEB ?
A) By taking section b-b and using ME = 0
B) By taking section b-b, and using FX = 0 and FY = 0
C) By taking section a-a and using MB = 0
D) By taking section a-a and using MD = 0
ATTENTION QUIZ
1. As shown, a cut is made
through members GH, BG
and BC to determine the
forces in them. Which section
will you choose for analysis
and why?
A) Right, fewer calculations.
B) Left, fewer calculations.
C) Either right or left, same
amount of work.
D) None of the above, too
many unknowns.
ATTENTION QUIZ
2. When determining the force in
member HG in the previous
question, which one equation of
equilibrium is best to use?
A) MH = 0
B) MG = 0
C) MB = 0
D) MC = 0
READING QUIZ
1. Frames and machines are different as compared to trusses since they
have ___________.
A) Only two-force members B) Only multiforce members
C) At least one multiforce member D) At least one two-force
member
2. Forces common to any two contacting members act with _______
on the other member.
A) Equal magnitudes but opposite sense
B) Equal magnitudes and the same sense
C) Different magnitudes but opposite sense
D) Different magnitudes but the same sense
CONCEPT QUIZ
1. The figures show a frame and its FBDs. If an additional couple
moment is applied at C, then how will you change the FBD of
member BC at B?
A) No change, still just one force (FAB) at B.
B) Will have two forces, BX and BY, at B.
C) Will have two forces and a moment at B.
D) Will add one moment at B.
2. The figures show a frame and its FBDs. If an additional force is
applied at D, then how will you change the FBD of member BC
at B?
A) No change, still just one force (FAB) at B.
B) Will have two forces, BX and BY, at B.
C) Will have two forces and a moment at B.
D) Will add one moment at B.
CONCEPT QUIZ (continued)
D
ATTENTION QUIZ
2. For the above problem, imagine that you have drawn a FBD
of member AB. What will be the easiest way to write an
equation involving unknowns at B?
A) MC = 0 B) MB = 0
C) MA = 0 D) FX = 0
1. When determining the reactions
at joints A, B, and C, what is the
minimum number of unknowns
for solving this problem?
A) 3 B) 4
C) 5 D) 6
READING QUIZ
1. A friction force always acts _____ to the contact surface.
A) Normal B) At 45°
C) Parallel D) At the angle of static friction
2. If a block is stationary, then the friction force acting on it is
________ .
A) s N B) = s N
C) s N D) = k N
CONCEPT QUIZ
1. A 100 lb box with a wide base is pulled by a force P
and s = 0.4. Which force orientation requires the
least force to begin sliding?
A) P(A) B) P(B)
C) P(C) D) Can not be determined
P(A)
P(B)
P(C) 100 lb
2. A ladder is positioned as shown. Please indicate
the direction of the friction force on the ladder at
B.
A) B)
C) D)
A
B
ATTENTION QUIZ
2. The ladder AB is postioned as shown. What is the
direction of the friction force on the ladder at B.
A) B)
C) D) A
B
1. A 10 lb block is in equilibrium. What is
the magnitude of the friction force
between this block and the surface?
A) 0 lb B) 1 lb
C) 2 lb D) 3 lb
S = 0.3
2 lb
READING QUIZ
1. A wedge allows a ______ force P to lift
a _________ weight W.
A) (large, large) B) (small, small)
C) (small, large) D) (large, small)
2. Considering friction forces and the
indicated motion of the belt, how are belt
tensions T1 and T2 related?
A) T1 > T2 B) T1 = T2
C) T1 < T2 D) T1 = T2 e
W
CONCEPT QUIZ
2. The boy (hanging) in the picture weighs
100 lb and the woman weighs 150 lb. The
coefficient of static friction between her
shoes and the ground is 0.6. The boy will
______ ?
A) Be lifted up B) Slide down
C) Not be lifted up D) Not slide down
1. Determine the direction of the friction
force on object B at the contact point
between A and B.
A) B)
C) D)
ATTENTION QUIZ
2. In the analysis of frictional forces on a flat belt, T2 = T1 e .
In this equation, equals ______ .
A) Angle of contact in degrees B) Angle of contact in radians
C) Coefficient of static friction D) Coefficient of kinetic friction
1. When determining the force P needed to lift the
block of weight W, it is easier to draw a FBD
of ______ first.
A) The wedge B) The block
C) The horizontal ground D) The vertical wall
W
READING QUIZ
1. A screw allows a ______ moment M to
lift a _________ weight W.
A) (large, large) B) (small, small)
C) (small, large) D) (large, small)
2. A screw is self locking if it remains in
place under __________ loads.
A) any axial B) small axial
C) any rotational D) small rotational
W