For a classroom demonstration, a student sits on a piano stool holding a sizeabl
ID: 1293178 • Letter: F
Question
For a classroom demonstration, a student sits on a piano stool holding a sizeable mass in each hand. Initially the student holds his arms outstretched and spins about the axis of the stool with an angular speed of 3.85 rad/s. The moment of inertia in this case is 5.6 kg m2. While still spinning the student pulls his arms to his chest, reducing the moment of interim to 2.0 kg m2. What is the students angular speed now? For a classroom demonstration, a student sits on a piano stool holding a sizeable mass in each hand. Initially the student holds his arms outstretched and spins about the axis of the stool with an angular speed of 3.85 rad/s. The moment of inertia in this case is 5.6 kg m2. While still spinning the student pulls his arms to his chest, reducing the moment of interim to 2.0 kg m2. What is the students angular speed now?Explanation / Answer
initial angualr momentum Li= I1*w1
final angular momentum lf = I2*w2
from momentum conseravation
Lf = li
I2*w2 = I1*w1
w2 = (I1*w1)/I2
w2 = (5.6*3.85)/2
w2 = 10.78 rad/s