1. The problem statement, all variables and given/known data Consider a simple helicopter blade, attached to a bolt at its end. The bolt is made to rotate by a powerful motor, and the blade therefore rotates. The blade has a length L= 7.8 m and mass M= 100 kg. The blade is shaped approximately like a long thin, uniform rod. What torque must the bolt exert on the blade in order to bring it from rest to full angular speed 320 rev/min in time t= 6.70 s 2. Relevant equations Before, I worked out the force that ther bolt exerts on the blade when the blade is spinning at full speed to be 4.4 x 10^5 N. thus, force= 4.4 x 10^5 N. I thought that i could just find the angular acceleration: wf=wi + at and then find the moment of inertia and use T=Ia but i dont know what the moment of inertia would be. Would it be 1/12mL^2 or 1/3mL^2 3. The attempt at a solution I found the angular acceleration to be 5/rad/s^2.. but i just dont know what the moment of inertia would be becoz i worked them out using the above equations and i keep getting the wrong answer. the right answer is 7.6 x 10^3 N.m. Is T=Ia the right forumla to be using or am i on the wrong track? Any help would be muchly appreciated! thankyou!