Question

Celia is staring at the clock waiting for school to end so that she can go to track practice. She notices that the 4-inch-long minute hand is rotating around the clock and marking off time like degrees on a unit circle. Part 1: How many radians does the minute hand move from 1:25 to 1:50? (Hint: Find the number of degrees per minute first.) Part 2: How far does the tip of the minute hand travel during that time?

Answer 1

there are 60 minutes marks on a clock

 360/60 = 6

 6 degree between every minute

 From 1:25 to 1:50 there are 25 minutes

25 x 6 = for a total of 150 degrees

150*pi/180 = 5pi/6 radians. ( 2.61799 radians)

 

Total distance the tip of minute hand has traveled in this time = 2pi*(4 in) * (5pi/6)/(2pi) = 10pi/3 inches (10.47 inches)