We know that torque in an induction machine varies as \$k\times[\cos(2wt)+\cos(\beta)]\$ but we don't feel it. Why it's so?
Evaluate that for 60 hz on an actual machine. Account for the rotational inertia of the rotor mass. Consider that momentum is like a bucket - if you add a drop and lose a drop 60 times a second, nobody is going to see the level change unless they are really looking for it.