Fundamental Engineering Concepts - Mathematics and Statistics for the Environment - page 237

TABLE 11.1
Alloy Steel Chain Sling Load Angle Factors a

Horizontal Sling Angle Load Angle Factor

90° 1.000

85° 1.004

80° 1.015

75° 1.035

70° 1.064

65° 1.104

60° 1.155

55° 1.221

50° 1.305

45° 1.414

40° 1.555

35° 1.742

30° 2.000

25° 2.364 b

20° 2.924 b

15° 3.861 b

10° 5.747 b

5° 11.490 b

Source: PNNL, PNNL Hoisting and Rigging Manual ,
Pacific Northwest National Laboratory, Richland,
WA, 2013 (http://www.pnl.gov/contracts/hoist_
rigging/slings.asp).
a Tension in each sling leg = Load/2 = Load angle factor.
b Not recommended.

■ EXAMPLE 11.6
Problem : We assume that a fully loaded cart weighing 400 lb is to be pulled up a ramp that has a
5-ft rise for each 12 ft, measured along the horizontal direction (make a rough drawing; see Figure
11.6). What force is required to pull it up the ramp?

Note: For illustrative purposes, we assume no friction. Without friction, of course, the work done
in moving the cart in a horizontal direction would be zero; once the cart was started, it would
move with constant velocity—the only work required is that necessary to get it started.
However, a force equal to J is necessary to pull the cart up the ramp or to maintain the car at

F normal

F gravity

FIGURE 11.5 Forces acting on an inclined plane.