Given,
Revolution/ min = 360 times
To find,
No of revolutions in 3 sec = ? (in radians)
Solution,
We know that it takes 60 sec to complete 360 revolutions.
1 revolution = 360° (i)
And,
360° = 2π radians (ii)
From (i) and (ii)
1 revolution = 2π radians
By using unitary method,
1 revolution→ 2π radians
360 revolution→ ?
∵ No. of radians covered by 360 revolutions in 60 secs is 720 π radians.
By using unitary method again,
60 secs→720 π radians
3 secs→ ?
Therefore, in 3 secs the wheel will cover 12 π radians.