MechE Mat Quiz 5
False
A flat bar with shoulder fillets can support a larger bending moment if the fillet radius is decreased.
True
A flat bar with shoulder fillets can support a larger bending moment if the fillet radius is increased.
eccentric axial load
An axial force whose line of action does not pass through the centroid of a cross section is called _______.
False
An imbalance in the bending stress resultant forces acting on a portion of a beam's cross section demands an internal horizontal shear force for elasticity.
True
An imbalance in the bending stress resultant forces acting on a portion of a beam's cross section demands an internal horizontal shear force for equilibrium.
shear force
An internal _______ acts on a surface parallel to its line of action.
2 in.
Assume the following beam cross section experiences a vertical shear force. What is the value of t (in τ = VQ/It) for determining the largest horizontal shear stress? (9.7 Q6)
4 in.
Assume the following beam cross section experiences a vertical shear force. What is the value of t (in τ = VQ/It) for determining the largest horizontal shear stress?(9.7 Q10)
80 mm
Assume the following beam cross section experiences a vertical shear force. What is the value of t (in τ = VQ/It) for determining the largest horizontal shear stress?(9.7 Q11)
40 mm
Assume the following beam cross section experiences a vertical shear force. What is the value of t (in τ = VQ/It) for determining the largest horizontal shear stress?(9.7 Q7)
4.0 in.
Assume the following beam cross section experiences a vertical shear force. What is the value of t (in τ = VQ/It) for determining the largest horizontal shear stress?(9.7 Q8)
80 mm
Assume the following beam cross section experiences a vertical shear force. What is the value of t (in τ = VQ/It) for determining the largest horizontal shear stress?(9.7 Q9)
4.0 in.
Assume the following beam cross section experiences a vertical shear force. What is the value of t (in τ = VQ/It) for determining the largest horizontal shear stress?(9.8 Q1)
4 in.
Assume the following beam cross section experiences a vertical shear force. What is the value of t (in τ = VQ/It) for determining the largest horizontal shear stress?(9.8 Q2)
80 mm
Assume the following beam cross section experiences a vertical shear force. What is the value of t (in τ = VQ/It) for determining the largest horizontal shear stress?(9.8 Q3)
2
Assuming each grid line is one unit long, determine the value of t in the horizontal shear stress formula at the point indicated by τ. (9.7 Q1)
2
Assuming each grid line is one unit long, determine the value of t in the horizontal shear stress formula at the point indicated by τ. (9.7 Q2)
1
Assuming each grid line is one unit long, determine the value of t in the horizontal shear stress formula at the point indicated by τ. (9.7 Q3)
4
Assuming each grid line is one unit long, determine the value of t in the horizontal shear stress formula at the point indicated by τ. (9.7 Q4)
2
Assuming each grid line is one unit long, determine the value of t in the horizontal shear stress formula at the point indicated by τ. (9.7 Q5)
False
Axial forces cannot produce bending stresses.
two tension
Corner H experiences _______ normal stress(es). (8.7 Q18)
one tension and one compression
Corner K experiences _______ normal stress(es). (8.7 Q19)
True
Discontinuities can produce stress concentrations.
False
Discontinuities cannot produce stress concentrations.
True
Fasteners in built-up flexural members transmit internal horizontal forces.
bh^2/8
For a rectangular cross section of width b and height h, the largest first moment of area Q is _______.
bending moment, axial load and eccentricity
For the equation M=Pxe , what do M, P and e represent?
True
If a beam is in equilibrium, then any portion of the beam that we choose to consider must also be in equilibrium.
True
If there is a horizontal shear stress there will also be a vertical shear stress.
False
In beams with circular cross sections, transverse shear stress acts parallel to the y axis over the entire depth of the shape.
False
In portions of a beam where the internal bending moment is zero, an internal shear force will be present.
True
Internal bending moments are usually accompanied by internal shear forces.
False
Near notches, grooves and fillets, the normal stress due to bending can be ignored.
True
Near notches, grooves and fillets, the normal stress due to bending can be significantly greater than the nominal stress.
True
Nonuniform bending produces both shear stresses and normal stresses.
two tension
Point A experiences _______ normal stress(es). (8.7 Q20)
one tension and one compression
Point A experiences _______ normal stress(es). (8.7 Q22)
one tension and one compression
Point B experiences _______ normal stress(es). (8.7 Q21)
two compression
Point B experiences _______ normal stress(es).(8.7 Q23)
two compression
Point H experiences _______ normal stress(es). (8.7 Q24)
one tension and one compression
Point K experiences _______ normal stress(es). (8.7 Q25)
True
Pure bending is less common than nonuniform bending.
False
Pure bending is more common than nonuniform bending.
first
Q is the _______ moment of area.
-P (y + t/2)
Select the bending moment that would be used to calculate the bending stress along line a-a. (8.7 Q3)
-P (46 mm)
Select the bending moment that would be used to calculate the bending stress at corner H.(8.7 Q4)
-P (46 mm)
Select the bending moment that would be used to calculate the bending stress at corner K. (8.7 Q5)
-(6 kN)(28 mm)
Select the bending moment that would be used to calculate the bending stress at point A. (8.7 Q6)
(12 kN)(176 mm)
Select the bending moment that would be used to calculate the bending stress at point A.(8.7 Q8)
-(6 kN)(28 mm)
Select the bending moment that would be used to calculate the bending stress at point B. (8.7 Q7)
(12 kN)(176 mm)
Select the bending moment that would be used to calculate the bending stress at point B. (8.7 Q9)
(1,200 lb)(16 in.)
Select the bending moment that would be used to calculate the bending stress at point H. (8.7 Q10)
(1,200 lb)(16 in.)
Select the bending moment that would be used to calculate the bending stress at point K. (8.7 Q11)
(2 kips)(24 in.) - (19.5 kips)(16 in.)
Select the bending moment that would be used to calculate the bending stress on plane H-K. (8.7 Q2)
(30 kips)(8 in.)
Select the bending moment that would be used to calculate the bending stress on plane a-a. (8.7 Q1)
bt^3/12
Select the moment of inertia that would be used to calculate the bending stress along line a-a.(8.7 Q12)
((120 mm)(14 mm)^3)/12
Select the moment of inertia that would be used to calculate the bending stress at point A. (8.7 Q13)
((112 mm)(72 mm)^3)/12
Select the moment of inertia that would be used to calculate the bending stress at point A. (8.7 Q15)
((120 mm)(14 mm)^3)/12
Select the moment of inertia that would be used to calculate the bending stress at point B. (8.7 Q14)
((4 in.)(8 in.)^3)/12
Select the moment of inertia that would be used to calculate the bending stress at point H. (8.7 Q16)
((4 in.)(8 in.)^3)/12
Select the moment of inertia that would be used to calculate the bending stress at point K. (8.7 Q17)
per unit length
Shear flow q is the shear force _______ of the beam span required to satisfy horizontal equilibrium.
True
Shear stress acts on both transverse and longitudinal planes.
True
Shear stress intensity is distributed parabolically on rectangular cross sections.
True
Shear stress is often assumed to be constant across the width of a beam's cross section at any specific y position.
False
Shear stresses develop on free surfaces.
True
Shear stresses on perpendicular planes are equal in magnitude.
away from
The area used to calculate Q extends _______ the neutral axis.
(F/A)-(My/Iz)
The complete stress distribution obtained by superposing the stresses produced by an axial force and a bending moment is correctly represented by _______.
zero
The first moment of the total cross-sectional area taken about the neutral axis must be _______.
web
The formula τ = VQ/Izt can be used to determine the shear stress in the _______ of a flanged beam bent about its strong axis.
True
The horizontal shear stress and the transverse shear stress at a particular point are equal in magnitude.
True
The key to correctly calculating Q for a built-up flexural member is to determine which portion of the cross section is being held in place by a particular fastener.
less than
The magnitude of Q for a hollow circular cross section will be _______ the magnitude of Q for a solid circular cross section with the same outside diameter.
False
The maximum horizontal shear stress occurs on a free surface of a beam.
False
The neutral axis is always found at the centroid of a beam.
entire cross section
The term Iz in the formula τ=VQ/Izt is the moment of inertia of the _______ about the z centroidal axis.
False
The volume of a stress distribution is equal to a bending moment.
True
The volume of a stress distribution is equal to a force.
True
Whenever an internal axial force F acts simultaneously with an internal bending moment M, the neutral axis is no longer located at the centroid of the cross section.
point C
Which point experiences the largest horizontal shear stress? (9.5 Q1)
rectangular cross sections
τmax = 3V/2A is appropriate to use with _______.
circular cross sections
τmax = 4V/3A is appropriate to use with _______.