Answer
(a). 271 Nm
(b). $54.936 \frac{kN}{m^3}$
(c). 0.678 mm/s
Work Step by Step
(a). $200lb.ft \times \frac {4.448N}{1lb} \times \frac{1m}{3.28ft}=271 Nm$
(b). $350 \frac{lb}{ft^3} \frac{3.28^3ft^3}{1m^3}\frac{4.448N}{1lb}\times \frac{1kN}{1000N}=54.936 kN/m^3$
(c). $8ft/h \times \frac{1m}{3.28ft} \times \frac{1000mm}{1m} \times \frac {1h}{3600s}=0.677mm/s$