1. Mechanical Engineering
Tutorial 4
Moment of a force
Harem Gh. Hussein
22- Jan-2015

2. Statics’ Subtopics 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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3. Problem 1
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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4. Solution 1
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5. Problem 2
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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6. Solution 2
Maximum Moment
Minimum Moment
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7. Solution 2
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8. Solution 2
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9. Problem 3
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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10. Solution 3
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11. Solution 3
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12. Problem 4
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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13. Solution 4
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14. Problem 5
Determine the required magnitude of force F if the resultant couple moment on the frame is200 lb.ft clockwise.
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15. Solution 5
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16. Problem 6
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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17. Solution 6
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18. Problem 7
Determine the required magnitude of force F, if the resultant couple moment on the beam is to be zero.
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19. Solution 7
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20. Solution 7
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21. Problem 8
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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22. Solution 8
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23. Any Question?
Thank you!
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