Q1.
You might have noticed that sometimes the wind is so strong that it is difficult to walk against it. Can you think of some other times when strong winds have caused problems for you?
Answer
Yes — and Table 3.1 lets you name the strength as well as the problem, because it pairs each wind speed with the effects you would actually see.
| Wind | Speed (km/hr) | Problems it causes, from Table 3.1 and everyday life |
|---|---|---|
| Calm | 0 – 1 | No problem at all — smoke rises straight up. But on a hot, still day there is no breeze to cool you either |
| Light breeze | 6 – 11 | Leaves rustle and you can feel it on your face. Loose papers and homework sheets blow off the desk |
| Strong breeze | 39 – 49 | Umbrellas are difficult to use and large branches sway — this is the wind that turns an umbrella inside out on the way to school, and makes cycling into it hard work |
| Storm | 103 – 117 | Very rarely experienced, and usually accompanied by widespread damage — uprooted trees, blown-off roofs, snapped power lines, cancelled trains and flights |
Everyday examples worth mentioning in your discussion: dust blown into the eyes on a windy afternoon; washing pulled off the line; a badminton or cricket match spoiled because the ball keeps drifting; kites cut loose or torn on Makar Sankranti; a power cut after a storm brings down a line; and — as the chapter says at the start of the Wind section — trees uprooted during a storm.
Why walking into wind is so much harder than walking with it: the wind pushes on the whole front of your body, and that push grows very steeply as the wind speeds up — a strong breeze of 45 km/hr does not push twice as hard as one of 22 km/hr, but far more. That is why the jump from a light breeze (6–11 km/hr) to a storm (103–117 km/hr) in Table 3.1 is not a jump from 'noticeable' to 'annoying' but from 'leaves rustle' to 'widespread damage'.
Check it yourself: notice how Table 3.1 leaves gaps — nothing is listed between 1 and 6, between 11 and 39, or between 49 and 103 km/hr. Those gaps are the missing categories the next LET'S EXPLORE box asks you to find.