This is a very confusing problem, I had never taken physics before and it is going to kill my GPA. can someone please help me solve this problem. I have a quiz coming up. Thanks for the help.
The flywheel of an old steam engine is a solid homogeneous metal disk of mass M = 137 kg and radius R = 90.1 cm. The engine rotates the wheel at 413 rpm. In an emergency, to bring the engine to a stop, the flywheel is disengaged from the engine and a brake pad is applied at the edge to provide a radially inward force F = 109 N.
a) If the coefficient of kinetic friction between the pad and the flywheel is μk = 0.353, how many revolutions does the flywheel make before coming to rest?
b) How long does it take for the flywheel to come to rest?
c) Calculate the work done by the torque during this time.
1 answer
parameter:m-137kg r-0.901m coeff-0.353m normal force-109N angular velocity-413rpm=43.25rad/s Torque exerted by friction=moment of inertiaI*angular acceleration Ffr=0.353*109=38.48N I=1/2MR^2=0.5*137*0.901^2=55.61Kgm^2 38.48*0.901=55.61*angular acceleration angular acceleration=0.6235rad/s^2(caused by friction) 43.25^2=4*0.6235*3.14n n=1871/7.83=239revs b) t=w/0.6235=43.25/0.6235=69.4secs c)W=Ffr*R*w=38.48*0.901*43.25*69.4=1.04*10^5J
3 answers