Exercise 10.20 A string is wrapped several times around the rim of a small hoop
ID: 1473745 • Letter: E
Question
Exercise 10.20
A string is wrapped several times around the rim of a small hoop with radius 8.00 cm and mass 0.180 kg . The free end of the string is held in place and the hoop is released from rest (the figure (Figure 1) ). After the hoop has descended 60.0 cm , calculate
Part A
the angular speed of the rotating hoop and
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Part B
the speed of its center.
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Figure 1 of 1
Exercise 10.20
A string is wrapped several times around the rim of a small hoop with radius 8.00 cm and mass 0.180 kg . The free end of the string is held in place and the hoop is released from rest (the figure (Figure 1) ). After the hoop has descended 60.0 cm , calculate
Part A
the angular speed of the rotating hoop and
= rad/sSubmitMy AnswersGive Up
Part B
the speed of its center.
v = m/sSubmitMy AnswersGive Up
Provide FeedbackContinue
Figure 1 of 1
Explanation / Answer
B)
Apply conservation of energy
final kinetic energy = initial potentail energy
0.5*m*v^2 + 0.5*I*w^2 = m*g*h
0.5*m*v^2 + 0.5*m*r^2*w^2 = m*g*h
0.5*m*v^2 + 0.5*m*v^2 = m*g*h
m*v^2 = m*g*h
==> v = sqrt(g*h)
= sqrt(9.8*0.6)
= 2.42 m/s <<<<<<<-------Answer for part B)
A) we know, Vcm = r*w
==> e = Vcm/r
= 2.42/0.08
= 30.3 rad/s <<<<<<<-------Answer for part A)
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