16 USEFUL MATH [CHAP. 1 11 8 1.11. 1.5 × 10 km; 1.5 × 10 m 1.12. 35.3ft 3 1.13. 37 mi/h 8 8 5 1.14. 9.84 × 10 ft/s; 1.86 × 10 mi/s; 6.72 × 10 mi/h 1.15. 9.2 mi/h; 13.5 ft/s 1.16. (a)90 (b) 103 (c)4.0 × 10 9 (d)6.37 × 10 4 (e) 6.6