Question

The second hand of the watch is 2 cm long. How far the tip will move in 40 seconds?

(a) 6.28 cm

(b) 12.56 cm

(c) 3.14 cm

(d) 1.57 cm

This question was addressed to me by my college director while I was bunking the class.

This interesting question is from Trigonometric Functions topic in section Trigonometric Functions of Mathematics – Class 11

Answer 1

Right option is (b) 12.56 cm

For explanation I would say: Radius of circle=2 cm

In 60 seconds, angle covered by second hand is 360°

In 40 seconds, angle covered by second hand is 360°*4/6 = 240°

240°=240*

Angle=Arc length/Radius

240*π/180 = Arc length/2

Arc length=8 π/3 = 12.56 cm.