Answer:r'=0.327 m
Step-by-step explanation:
Given

angular velocity 
mass of objects 
distance of objects from stool 
Combined moment of inertia of stool and student 
Now student pull off his hands so as to increase its speed to 3.60 rev/s


Initial moment of inertia of two masses 

After Pulling off hands so that r' is the distance of masses from stool

Conserving angular momentum








The percentage change in volume from cylinder A to cylinder B; D: 100%
<h3>How to find the percentage change in Volume?</h3>
Formula for Volume of a Cylinder is;
V = πr²h
Thus, volume of Cylinder A is;
V_a = π * 7² * 5
V_a = 245π
Thus, percentage change in volume is;
[245π/(490π - 490π)] * 100%
Percentage change in volume = 100%
Read more about percentage change in volume at; brainly.com/question/9554871
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I think it’s A I’m not 100 percent sure tho sorry if I’m wrong
That is the vertex form of a quadratic equation