Page 28 - Dynamics of Mechanical Systems

0593_C01_fm Page 9 Monday, May 6, 2002 1:43 PM

Introduction 9

1.7 Systems of Units
In this book, we will use both the English and the International unit systems. On occasion,
we will want to make conversions between them. Table 1.7.1 presents a listing of unit
conversion factors for commonly occurring quantities in mechanical system dynamics.

TABLE 1.7.1
Conversion Factors between English and International Unit Systems
To Convert Multiply by
from to
2
*
Acceleration (L/T ) ft/sec 2 m/sec 2 3.048 000 × 10 –1
*
ft/sec 2 cm/sec 2 3.048 000 × 10 1
*
ft/sec 2 in./sec 2 1.200 000 × 10 1
ft/sec 2 g 3.105 590 × 10 –2
m/sec 2 ft/sec 2 3.280 840 × 10 0
m/sec 2 in./sec 2 3.937 008 × 10 1
*
m/sec 2 cm/sec 2 1.000 000 × 10 2
m/sec 2 g 1.018 894 × 10 –1
in./sec 2 ft/sec 2 8.333 333 × 10 –2
*
in./sec 2 m/sec 2 2.540 000 × 10 –2
*
in./sec 2 cm/sec 2 2.540 000 × 10 0
in./sec 2 g 2.587 992 × 10 –3
cm/sec 2 ft/sec 2 3.280 840 × 10 –2
cm/sec 2 in./sec 2 3.937 008 × 10 –1
*
cm/sec 2 m/sec 2 1.000 000 × 10 –2
cm/sec 2 g 1.018 894 × 10 –3
*
g ft/sec 2 3.220 000 × 10 1
*
g in./sec 2 3.864 000 × 10 2
g m/sec 2 9.814 564 × 10 0
g cm/sec 2 9.814 564 × 10 –2
Angular velocity (1/T) rpm rad/sec 1.047 198 × 10 –1
rad/sec rpm 9.549 297 × 10 0
Angle deg rad 1.745 329 × 10 –2
rad deg 5.729 578 × 10 1
Area ft 2 m 2 9.290 304 × 10 –2
ft 2 cm 2 9.290 304 × 10 2
*
in. 2 m 2 6.451 600 × 10 –4
*
in. 2 cm 2 6.451 600 × 10 0
*
ft 2 in. 2 1.440 000 × 10 2
in. 2 ft 2 6.944 444 × 10 –3
m 2 ft 2 1.076 391 × 10 1
m 2 in. 2 1.550 003 × 10 3
*
m 2 cm 2 1.000 000 × 10 4
cm 2 ft 2 1.076 391 × 10 –3
–1
cm 2 in. 2 1.550 003 × 10
*
cm 2 m 2 1.000 000 × 10 –4
Energy/work ft lb Nm (or J) 1.355 818 × 10 0
in. lb Nm (or J) 1.129 848 × 10 –1
*
ft lb in. lb 1.200 000 × 10 1
in. lb ft lb 8.333 333 × 10 –2
Nm (or J) ft lb 7.375 621 × 10 –1
Nm (or J) in. lb 8.850 745 × 10 0
Force lb N 4.448 222 × 10 0
N lb 2.248 089 × 10 –1