On a stopwatch, the tip of the second hand moves 2 cm in 15 seconds. how long is the second hand (to the nearest tenth)? a. 1.3 cm. b. 6.3 cm. c. 12.6 cm. d. 30.0 cm

We are asked to determine the length of the second hand when it has moved 2 cm in 15 seconds. The movement in 15 seconds generates an angle of 90 degrees or pi / 2. we apply the equation of arc length which is 2 cm; s = 2= r theta = r* pi /2 where r is the second hand length. The answer is 1.27 cm closest to A

Clever question.  Pretty simple, but we never think of the details
quite in this order.

-- The 'seconds' hand on the watch goes all the way around in 1 minute.
The tip of the hand moves in a circle.

-- 15 seconds is 1/4 of a complete 1-minute revolution. 
So the 2 cm is 1/4 of the way around the circle that the tip makes.

--  The full circumference of the circle is 8cm.

-- The length of the second hand is the radius of the circle. 

                              2 pi radius  =  circumference

                               2 pi radius  =  8 cm
Divide each side
by  2 pi :                        radius  =  8cm / 2 pi  =  1.27 cm
                                                                             (choice - A)

The correct answer should be b let me know if i’m wrong

Caused conformity rates to go down. apex ; )