Sol Cap 02 - Edicion 8

COSMOS: Complete Online Solutions Manual Organization System
Chapter 2, Solution 98.
Have T = T ( sin 50° cos 40° i − cos50° j + sin 50° sin 40°
k )
AB
AB
( 980 lb)( cos 45 sin 25 sin 45 cos 45 cos 25 )
T AC = − ° ° i − ° j + ° ° k
(a) R = T + T
( R ) = 0
A AB AC A x
AB
( R ) F 0:
∴ = Σ =
A
x
( )
T sin 50° cos 40° − 980 lb cos 45° sin 25° = 0
x
or
T AB =
499.06 lb
∴ = 499 lb ⊳
T AB
(b) ( RA) F
y y ( ) ( )
( R A) y
=− 1013.75 lb
( RA) F
z z ( ) ( )
( R A) z
= 873.78 lb
∴ R = − ( 1013.75 lb) j + ( 873.78 lb)
k
Then
and
A
=Σ =− 499.06 lb cos50°− 980 lb sin 45°
=Σ = 499.06 lb sin 50° sin 40°+ 980 lb cos 45° cos 25°
R = 1338.35 lb
R = 1338 lb ⊳
A
0
cosθ x = θ x = 90.0°⊳
1338.35 lb
A
cos
θ y
−1013.75 lb
= θ y = 139.2°⊳
1338.35 lb
873.78 lb
cosθ z = θ z = 49.2°⊳
1338.35 lb
Vector Mechanics for Engineers: Statics and Dynamics, 8/e, Ferdinand P. Beer, E. Russell Johnston, Jr.,
Elliot R. Eisenberg, William E. Clausen, David Mazurek, Phillip J. Cornwell
© 2007 The McGraw-Hill Companies.