1] what is the magnitude of the initial angular velocity (before the masses were
ID: 1385147 • Letter: 1
Question
1] what is the magnitude of the initial angular velocity (before the masses were dropped)?
2] what is the final angular velocity?
please show full explanation and steps for answer
Cassandra stands on the center of a frictionless rotating platform that is rotating at a speed of 3 rad/s. Originally her arms are outstretched and she holds a 4.54-kg mass in each hand. She then d ops the masses on to the floor (not platform). Assume the moment of inertia of Cassandra, including her arms, is 5.42 kg . m^2. The original distance of the weights from the axis is 0.914 m.Explanation / Answer
What you want to calculate in this question is not given so i'm answering according to that what i got from this information.
Here w1 = initial angular velocity ( the velocity when she carried the masses) = 3 rad/ s
w2 = ? ( the angular velocity by which the plateform rotate when she drop the masses)
By principle of conservation of angular momentum,
I1 w1 = I2 w2 ------------------------------1
I1 = initial moment of interia ( ie moment of interia of Cassandra and masses she carried)
I1 = I + m1*r12 + m2*r2 -----------------------------2
I = moment of interia of cassandra and her arms = 5.42 kg- m^2
m1 = m2 = masses she carried = 4.54 Kg
r1 = r2 = distances of weights from axis = 0.914 m
From eq. 2 , I1 = 5.42+ ( 4.54*0.9142 + 4.54*0.9142 )
I1 = 13 kg- m^2
I2 = moment of interia after droping the masses = I = 5.43 kg- m^2
by eq 1, I1 w1 = I2 *w2
13*3 = 5.42* w2
w2 ( angular velocity after droping the masses) = 7.198 rad/ s
we can also calculate change in Kinetic energy= I2 w22 - I1*w12
we can also calculte work done = change in k.E
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.