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(a) Find the torque as a function of time that the drive motor mustprovide while

ID: 1733506 • Letter: #

Question

(a) Find the torque as a function of time that the drive motor mustprovide while the block is sliding.
t N·m

(b) Find the value of this torqueat t = 425 s,just before the sliding block finishes its motion.
N·m

(c) Find the power which the drive motor must deliver as a functionof time.
t W/s

(d) Find the value of the power when the sliding block is justreaching the end of the slot.
W

(e) Find the string tension as a function of time.
t N/s

(f) Find the work done by the drive motor duringthe 425 s motion.
kJ

(g) Find the work done by the string brake on the slidingblock.
kJ

(h) Find the total work on the system consisting of the disk andthe sliding block.
kJ

Explanation / Answer

(a) torque = dL / dt =    d (m r2 ) /dt =            = m 2r dr/dt   =   2 m r v Now...      r = vt     so    torque = 2 m vt v =    2 m v2  t     m = 100     =2.70 rev/s = 16.965 rad/s      v = 0.0125m/s     so     torque = 2 * 100 * 16.965 *0.01252 * t   =                     =    0.530 t