Tutorial 4
Moment of a force
Harem Gh. Hussein
22- Jan-2015
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
Units system, force system, parallelogram law

Forces components, resultant of coplanar forces

Components of forces in space, moment of a force,
moment of couples

Equilibrium, free body diagram, friction

Centroids and Centers of gravity, centroids of area

Moment of Inertia

Second moment of area by integration radius of gyration
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The handle of the
hammer is subjected to
the force of F=20 lb
Determine the moment
of this force about the
point A.
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
Determine the angle θ
(0o≤ θ ≤180o) of the force
F so that it produces a
maximum moment and a
minimum moment about
point A. Also, what are the
magnitudes of these
maximum and minimum
moments?
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Maximum Moment
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Minimum Moment
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
In order to raise the lamp
post from the position
shown, the force F on the
cable must create a
counterclockwise moment
of 1500 lb.ft about point
A. Determine the
magnitude of F that must
be applied to the cable.
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
In order to hold the wheelbarrow in the
position shown, force F must produce a
counterclockwise moment of 200 N.m about
the axle at A. Determine the required
magnitude of force F.
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
Determine the
required magnitude of
force F if the resultant
couple moment on the
frame is200 lb.ft
clockwise.
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
Determine the resultant couple moment
acting on the beam. Solve the problem two
ways: (a) sum moments about point O; and
(b) sum moments about point A.
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
Determine the required magnitude of force F, if
the resultant couple moment on the beam is to
be zero.
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
Two couples act on the
frame. If d=4 , determine
the resultant couple
moment. Compute the
result by resolving each
force into x and y
components and (a)
finding the moment of
each couple and (b)
summing the moments of
all the force components
about point A.
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