CHAPTER XIV.
USEFUL NOTES, TABLES,
FORMULÆ, ETC.
§ 1. Comparative Velocities.
| Miles per hr. | Feet per sec. | Metres per sec. | ||
| 10 | = | 14·7 | = | 4·470 |
| 15 | = | 22 | = | 6·705 |
| 20 | = | 29·4 | = | 8·940 |
| 25 | = | 36·7 | = | 11·176 |
| 30 | = | 44 | = | 13·411 |
| 35 | = | 51·3 | = | 15·646 |
§ 2. A metre = 39·37079 inches.
In order to convert—
| Metres into | inches | multiply by | 39·37 |
| " | feet | " | 3·28 |
| " | yards | " | 1·09 |
| " | miles | " | 0·0006214 |
| Miles per | hour into | ft. per min. | multiply by | 88·0 |
| " | min. into | ft. per sec. | " | 88·0 |
| " | hr. into | kilometres per hr. | " | 1·6093 |
| " | " | metres per sec. | " | 0·44702 |
| Pounds into | grammes | " | 453·593 | |
| " | kilogrammes | " | 0·4536 | |
§ 3. Total surface of a cylinder = circumference of base × height + 2 area of base.
Area of a circle = square of diameter × 0·7854.