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• Cielo Garcia

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8/10/2013

PROBLEM 3.19 • The overhead electric hoist C rides along a track on the horizontal beam AB. In addition to the 500-kN vertical force carried by the hoist, the beam also supports the three vertical forces shown.

MECH 311 HOMEWORK Patricia Bianca B. Dela Cruz 3 ChE - A

PROBLEM 3.19

PROBLEM 3.19

• A. If x = 5m, determine the resultant of the four forces carried by the beam.

300 kN 2m

120 kN 8m

200 kN 4m

3m B

A x=5m 500 kN Rx = ƩFx = 0 kN Ry = ƩFy Ry = -300 kN – 500 kN – 120 kN – 200 kN Ry = -1120 kN

R = 1120kN 

PROBLEM 3.19 300 kN

PROBLEM 3.19 120 kN

200 kN

R = 1120 kN

A

2m

8m

4m

3m

d

B

A x=5m 500 kN

+ ƩM = 300(2) + 500(5) + 120(10) + 200(14)  A

= 7100 kN-m 

+ ƩM = Rd  +  A 7100 = 1120 x d

d = 6.34 m

1

8/10/2013

PROBLEM 3.19

PROBLEM 3.19

• FINAL ANSWER:

• B. Determine the distance x for which the resultant of the four forces would act at the center of the span AB.

R = 1120 kN A

d = 6.34 m

8.5 m

R = 1120 kN 8.5 m

A

B x 500 kN

PROBLEM 3.19 8.5 m

R = 1120 kN 8.5 m

A

B x 500 kN

R = 1120  + ƩMA = 300(2) + 120(10) + 200(14) + 500x  + ƩMA = 4600 + 500x  + + ƩMA = Rd   4600 + 500x = 1120(8.5)

-fin-

x = 9.84 m

2