Problema Solution
As a ball rolls along a straight track it makes 13 revolutions while traveling 109 mm. Find the radius of the ball.
Answer provided by our tutors
circumference = 2*PI*r where 'r' is the radius and 'PI' is the numeric constant approximated by 3.14
13 revolutions means a length of 13 circumferences, so let 'x' represent the circumference of the ball, then:
109 = 13x
x = 109/13 = 8.3846
knowing the circumference, we can solve for the radius:
(109/13) = 2*PI*r
solving for 'r' we have r=1.33
the radius of the ball is approximately 1.33 mm