The 50-lb is hosted by the pulley system and motor M. If the crate starts from r

Question

The 50-lb is hosted by the pulley system and motor M. If the crate starts from rest and by

constant acceleration attains a speed of 15 ft/s after rising s = 6 ft, determine the power

that must be supplied to the motor at this instant. The motor has an efficiency of ? = 0.76.

Neglect the mass of the pulleys and cable.

The 50-lb is hosted by the pulley system and motor M. If the crate starts from rest and by constant acceleration attains a speed of 15 ft/s after rising s = 6 ft, determine the power that must be supplied to the motor at this instant. The motor has an efficiency of ? = 0.76. Neglect the mass of the pulleys and cable.

Explanation / Answer

We have,

v2 = v02 + 2a (s - s0)

(15)2 = 0 + 2a(6-0), we get, a = 18.75 ft/s2

Now, F = ma

2T - 50 = 50 / 32.2 (18.75) gives us Tension T = 39.56lb

2sB + sm = l

2vB = - vm = 2(-15) = -vm

vm = 30 ft/sec

P0 = F .v = 30(22.69) = 680.94 ft lb/sec

Pi = 680 / 0.76 = 895.97 ft lb/sec (efficiency given = 0.76)

Pi = 1.63 horse power

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

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