Question

Full Problem Solving. Disk Plater Head Arm QUESTION 1: Exam-like question (multiple choice). Head actuator NO A hard drive (see figure) consists of a rigid circular platter (or disk) of radius R and thickness d, with a mass of M. In normal operating conditions, the hard drive spins at angular velocity w. Chassis During the crash the read/write head scrapes against the http www.computerhope.com disk with a coefficient of kinetic friction of Use and normal force of n. Assume that just before the head crash the disk is rotating at w, radians/second. You can ignore any friction at the bearing. For this situation, the frictional force fk due to the read/write head is perpendicular to the radius vector, so that the torque has a magnitude Trfk wherer is the distance of the head from the disk axis. The moment of inertia of a uniform disk of radius R and mass M is / = MR. a) What is the angular acceleration associated with the torque from the crashed disk head? b) Assuming the crash starts at time t = 0, what is the time tstop at which the disk stops? c) How many revolutions does the disk undergo after the head crashes but before it stops spinning? d) How much energy is dissipated as heat as the head rubs against the surface of the platter while the system slows to a halt?

Answer 1

2 bk I MR MR2 нp?o t a - 2 bk HR2 2 2Tb1e Ч122 HR 4T bk Wosk dame TO HR 4 2 4TEbk Scanned with CS CamScanner