\fdO'^ - Old Forge Coal Mines

172 ELEMENTARY MECHANICS.
(389) See Fig. 27. By rules 2 and 4, Art. 754, bc =
87 sin -23° = 87 X .39073 = 33.994 lb., ^ ^ = 87 cos 23° =
87 X .92050 = 80.084 15.
80 16,
Fig. 27.
(390) See Fig. 28. {b) By rules 2 and 4, Art. 754,
^ ^ = 325 sin 15° = 325 X . 25882 = 84. 12 lb. Ans.
{a) ac= 325 cos 15° = 325 X . 96593 = 313. 93 lb. Ans.
(391)
Use formula lO.
W 125