Materiales

16

C H .l

S TRESS

PROBLEMS
1 -1. D eter mine the resultant intern al torque acting on the
cross sections through points B and C.

*1-4. D etermine the resultant internal torque acting on
t he cross sections through points C and D o f t he shaft. T he
shaft is fix ed a t B.

Prob.I -1i
P rob.l-1
1 -2. A force of 80 N is s upported by t he bracket as shown.
Dete rmine theresultant internal loadin gs acting on the
section through point A .

1 -5. T he beam supports th e distributed load shown.
D et ermine the resultant internal load ings on the cross
section through point C. Assume the r ea ctions at the
supports A a nd B a re vertical.

1 -6. T he beam supports the distributed load shown.
D ete rmine the resultant internal load in gs o n the cross
sectionsthrough points D and E. A ssume the reactions at
the supports A a nd B a re vertical.
4001b/ft

I

.-.~

80 N

P rob.I-2

6 ft

1 -3. The beam A B is fixed to the wall and has a uniform
weight OL 80 l b /ft. I f t he trolley supports a load o f 1500 lb,
determine the resultant internal loadings acting on the cross
sections through points C and D.
1 - - - - - - 2 0 ft -- - - - --+- -lO f t
~5ft~ 1

A

P robs. 1 -5/1-6
1 -7. D etermine the resultant internal loadings on the cross
sec ti o n through point D o n membe r A B.

';' 1-8. D etermine the resultant internal loadings at cross
sections through points E and F o n the assembly.

~====~.~==================~ _ . ~======~~ B
_

c

D

lS00 1b

P rob.I-3

0.5 m 0.5 m 0.5 m

P robs. 1 -7/ - 8

PROBLEMS

1 -9. T he b oom D F o f the jib crane and the column D E
have a uniform weight o f 50 lblft. I f the hoist and load weigh
300 Ib, d etermine the resultant internal loadings in the crane

on cross sections through points A , B, and C.


17

1 -11. D etermine t he r esultant internal loadings acting on

the cross section at point B.


60lb/ft

•

·~-~~I =~~~l~~

F+--- - 8 ft --~
--j-t--

A

3 ft --1-- - - --

-12 ft

-----~

3001b

Prob . 1-11

E

Prob. I -9

1-10. D etermine the resultant internal loadings acting o n
the cross section at point C. T he cooling unit has a total
weight o f 52 kip and a center o f gravity at C.

*1-12. D etermine t he resultant internal loading on the
cross section through point C of the pliers. There is a pin a t
A , and the jaws at B a re smooth.
1-13. D etermine the resultant internal loading o n the
cross section through point D o f the pliers.

F

2 0N

1-

2 0N

Prob. 1 -10

80 mm

--+-3~00

Probs. 1 -12/1-13

18

C H . 1 STRESS

1 -14. T he 800-lb load is being hoisted at a constant speed
using the motor M , which has a weight o f 90 lb. D etermine
th eresultant internal loadings acting on the cross section
through point B in the beam. The beam has a weight o f
40 Ib/ft a nd is fixed to the wall at A .

1-18. T he sky hook is used to support the cable of a
scaffold over the side o f a building. If it consists o f a s mooth
rod that contacts the parapet o f a wall at points A , B , and
C, d etennine the normal force, shear force, andmoment on
the cross section a t points D and E.

1 -15. D etermine the resultant internal loadings acting on
th e cross section through points C and D o f the beam in
P rob . 1-14.
0.2m

~====~=========*==~p===~

- 1-- - - - ­ • D ; · ·· · :· . .:.

f..-4 ft

A

0.3 m

I

0.2 m

L

0 .25 ft

....

. ," ' .'

c
0.3m - 1

18 kN

Prob.1 -18
Prob.1-14/1-15

*1-16. Determine the normal . force, shear force, a nd
m oment at a section through point C. Take P = 8 kN .
B

1 -19. T he serving tray T used on an airplane is s upported
on each side by an arm. The tray is pin connected to the arm
a t A , a nd at B t here is a s mooth pin. (The pin can move
within the slot in the arms to permit folding the tray against
the front passenger seat when not in use.)...