The second hand on a clock is 5" long. How far does the tip of the second hand move in 25 seconds?

Question

The second hand on a clock is 5" long. 

How far does the tip of the second hand move in 25 seconds? 

Answer 1

The second hand makes one revolution per minute. Given the diameter, we can get the circumference: C = pi * d.

So the speed of the tip of the hand is C/60s = (pi*d)/60 inches per second. multiply by 25 seconds to get the answer,