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Yo-Yo Rotation

  • Thread starter meanswing
  • Start date
  • #1
10
0

Homework Statement



A yo-yo has mass of 400 kg and radius of 1.5m. Its axle of rotation has a radius of 0.1m. Its string is attached to a crane. What is its final velocity after it is released.
mass (m)=400 kg
Radius (R)= 1.5 m
axle of yo-yo (r)= 0.1 m
height (h)=57m
angular acceleration (x)= x

Homework Equations



F=ma; I=(1/2)mr^2; a=xr a/r=x



The Attempt at a Solution



F=ma ; Torque=Tr=Ix T=Ix/r

Fnet,y = mg - T = ma

mg - I(a/r)/r = ma

mg = ma + I(a/r)/r

mg/ (m + I/r^2) = a

mg/(m + (1/2)mr^2/r^2 ) = a

a = 6.53 m/s

This doesnt seem right. Can anyone show me my error?
 

Answers and Replies

  • #2
76
0
well you have calculated the accelertion whereas the question asks for final velocity ...
 
  • #3
10
0
lol . ok figured it out. i was also using lowercase r instead of uppercase R.
 

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