20 miles
(20 mi / hr) x (12 sec) x (5,280 ft / mi) x (1 hr / 3600 sec)= (20 x 12 x 5,280 / 3,600) (mi - sec - ft - hr / hr - mi - sec)= 352 ft
Acceleration = (change in speed) / (time interval)= (50 - 30) mph / 20 sec = (20 mi/hr) (1/3,600 hr/sec) (5,280 ft/mi) / (20 sec)= (20 x 5,280) / (3,600 x 20) (mi - hr - ft / hr - sec - mi - sec)= 1.4667 ft/sec2 (rounded, repeating)
greater by 20 feet
20 mi/h * (1 h / 3600 s) * (5280 ft / 1 mi) = 29.33 ft/sec
The formula to convert 21120 feet to miles 21,120 ft * 1 mi 5280 ft = 4 mi
6200 ft is bigger by 20 ft. 1 Mile = 5280 ft 5280 + 900 = 6180
26400 ft are in 5 miles. 5280 ft in one mile
Assuming that's 20 ft by 20 ft, 400 sq ft.
8500 ft / 5280 ft/mi = 1.61 mi
100 mi = 528,000 ft
1.62 mi = 8,553.6 ft