(a) 3 week to milliseconds(b) 381 ft / s to miles / h (c) 554 m^4 / (day ⋅ kg) to cm^4 / (min ⋅ g) Sol)(a) 1 week = 7 days, 1 day = 24 hours, 1 hour = 3600 sec, 1 sec = 1000 ms (b) 1 min = 60 sec, 3.2808 ft = 0.0006214 miles (c) 1 day = 24 hours, 1 hour = 60 min, 1 kg = 1000 g, 1 m^4 = 10^8 cm^4