Two disks are mounted (like a merry-go-round) on low-friction bearings on the sa

Question

Two disks are mounted (like a merry-go-round) on low-friction bearings on the same axle end can be brought together so that they couple and rotate as one unit. The first disk, with rotational inertia 3.83 kg m^2 about Its central axis, is set spinning counterclockwise (which may be taken as the positive direction) at 367 rev/min. The second disk, with rotational inertia 8.07 kg m^2 about its central axis. Is set spinning counterclockwise at 843 rev/min, They then couple together. (a) What is their angular speed after coupling? If instead the second disk is set spinning clockwise at 843 rev/min, what are their (b) angular velocity (using the correct sign for direction) and (c) direction of rotation after they couple together? (a) Number Units (b) Number Units (c)

Explanation / Answer

a) Iw = i1w1 + i2w2

w = [i1w1+i2w2]/[i1+i2]

= [3.83*367+8.07*843]/[3.83+8.07]

= 689.8 rev/min

= 689.8*2pi/60 rad/s

= 72.24 rad/s

b)w = [i1w1-i2w2]/[i1+i2]

= [3.83*367-8.07*843]/[3.83+8.07]

= -453.56 rev/min

= -453.56*2pi/60 rad/s

= -47.5 rad/s CCW

= 47.5 rad/s Clockwise

c) clockwise

= 72.24 rad/s

  

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.