Where:
F = mean dynamometer force over the measurement interval as measured by the dynamometer.
vfinal = roll surface speed at the end of the measurement interval to the nearest 0.01 mi/hr.
vinit = roll surface speed at the start of the measurement interval to the nearest 0.01 mi/hr.
[DELTA]t = elapsed time during the measurement interval to the nearest 0.01 s.
Example:
F = 1.500 lbf = 48.26 ft·lbm/s2
vfinal = 40.00 mi/hr = 58.67 ft/s
vinit = 10.00 mi/hr = 14.67 ft/s
[DELTA]t = 30.00 s
Ib = 32.90 lbm
Example:
Ibref = 32.96 lbm
Ibact = 32.90 lbm (from paragraph (c)(5) of this section)
40 C.F.R. §1066.250