A “blink of an eye” is a time interval of about 150 ms for an average adult. The “closure” portion of the blink takes only about 55 ms. Let us model the closure of the upper eyelid as uniform angular
acceleration through an angular displacement of 15°. 

(a) What is the value of the angular acceleration the eyelid undergoes while closing?

(b) What is the tangential acceleration of the edge of the eyelid while closing if the radius of the eyeball is 1.25 cm?