MOMENTS

1.) The 4-kN force F is applied at point A. Compute the moment of F about point O,

expressing it both as a scalar and as a vector quantity. Determine the coordinates of

the points on the x- and y-axes about which the moment of F is zero.

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Coordinates of intercepts : ( -1.3 , 0 ) , ( 0 , 0.78 )

2.) The rectangular plate is made up of 1-ft squares as shown. A 75-lb force is applied at

point A in the direction shown. Determine the moment of this force about point B

and about point C.

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3.) A prybar is used to remove a nail as shown. Determine the moment of the 60-lb

force about the point O of contact between the prybar and the small support block.

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4.) The entire branch OA has a mass of 180 kg with mass center at G. Determine the

moment of the weight of this branch about point O.

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5.) The 30-N force P is applied perpendicular to the portion BC of the bent bar.

Determine the moment of P about point B and about point A.

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Resultants

1.) Determine the resultant R of the three tension forces acting on the eye bolt. Find the

magnitude of R and the angle θx which R makes with the positive x-axis.

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2.) Determine and locate the resultant R of the two forces and one couple acting on the I-

beam.

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3.) If the resultant of the two forces and couple M passes through point O, determine M.

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4.) A commercial airliner with four jet engines, each producing 90 kN of forward thrust, is in

a steady, level cruise when engine number 3 suddenly fails. Determine and locate the

resultant of the three remaining engine thrust vectors. Treat this as a two-dimensional

problem.

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5.) While sliding a desk toward the doorway, three students exert the forces shown in the

overhead view. Determine the equivalent force-couple system at point A. Then

determine the equation of the line of action of the resultant force.

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Equilibriums

1.) The mass center G of the 1400-kg rear-engine car is located as show in the figure.

Determine the normal force under each tire when the car is in equilibrium. State any

assumptions.

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2.) A carpenter carries a 12-lb 2-in. by 4-in. board as shown. What downward force does

he feel on his shoulder at A?

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3.) A carpenter holds a 12-lb 2in. by 4-in. board as shown. If he exerts vertical forces on

the board, determine the forces at A and B.

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4.) The 450-kg uniform I-beam supports the load shown. Determine the reactions at the

supports.

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5.) The 20-kg homogeneous smooth sphere rests on the two inclines as shown.

Determine the contact forces at A and B.

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