A pulley consists of a uniform disk of mass 5 kg and radius0.12m. A cord wrapped

Question

A pulley consists of a uniform disk of mass 5 kg and radius0.12m. A cord wrapped around the pulley with force 45 N. The pulleyis initially stationary. Find (a) the torque, (b) the angularacceleration, (c) the angular velocity at t= 4 s, (d) the angularmomentum at t = 4 s. Find also (e) the work done by the cord duringone complete revolution, and (f) the angular velocity of the wheelwhen it's rotational kinetic energy is 50 J. The teacher told usthe answer to (c) 600 rad/s, (e) 34 J, (f) 53 rad/s. I have completely no idea how to do this question. I got thisquestion wrong on my homework. The teacher gave us the answers for(c), (e) and (f), but he did not show us how he got this answer. Ireally want to understand how to do this since soemthing similarwill be on my exam. Please help. A pulley consists of a uniform disk of mass 5 kg and radius0.12m. A cord wrapped around the pulley with force 45 N. The pulleyis initially stationary. Find (a) the torque, (b) the angularacceleration, (c) the angular velocity at t= 4 s, (d) the angularmomentum at t = 4 s. Find also (e) the work done by the cord duringone complete revolution, and (f) the angular velocity of the wheelwhen it's rotational kinetic energy is 50 J. The teacher told usthe answer to (c) 600 rad/s, (e) 34 J, (f) 53 rad/s. I have completely no idea how to do this question. I got thisquestion wrong on my homework. The teacher gave us the answers for(c), (e) and (f), but he did not show us how he got this answer. Ireally want to understand how to do this since soemthing similarwill be on my exam. Please help.

Explanation / Answer

a) =Fr =(45)(.12) =5.4 m*N
b)=Ialpha alpha= 5.4/(1/2*5*.12^2) alpha= 150 rad/sec^2
c) alpha= /t = (150)(4) =600 rad/sec
d) L= I L= (1/2*5*.12^2)(600) L= 21.6
e) Convert 1 rev/sec into radians.. 1rev/sec * 2pi= 2pi rad/sec
W= ()(theta) W= 5.5*2pi = 33.9 J
f) K= 1/2I^2 50= (1/2)(1/2*5*.12^2)^2 = 52.7 rad/sec

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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