In the following class, which you are to complete, the backing array will be created and populated with nones in the __init__ method, and the head and tail indexes set to sentinel values (you shouldn't need to modify enqueueing and dequeueing items will take place at the tail and head, with tail and head tracking the position of the most recently enqueued item and that of the next item to dequeue, respectively. to simplify testing, your implementation should make sure that when dequeuing an item its slot in the array is reset to none, and when the queue is emptied its head and tail attributes should be set to -1.

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Aflywheel accelerates for 5 seconds at 2 rad/s2 from a speed of 20 rpm. determine the total number of revolutions of the flywheel during the period of its acceleration. a.5.65 b.8.43 c. 723 d.6.86