Angular acceleration problem - fishing reel

[FlipStyle1308]

A fish takes the bait and pulls on the line with a force of 2.2 N. The fishing reel, which rotates counterclockwise without friction, is a solid cylinder of radius 0.049 m and mass 0.82 kg.

What is the angular acceleration of the fishing reel?

I used angular acceleration = RT/I, and got 54.7536 rad/s^2, but the answer is not correct. Anyone know why? Thanks!

 

[nrqed]

A fish takes the bait and pulls on the line with a force of 2.2 N. The fishing reel, which rotates counterclockwise without friction, is a solid cylinder of radius 0.049 m and mass 0.82 kg.

What is the angular acceleration of the fishing reel?

I used angular acceleration = RT/I, and got 54.7536 rad/s^2, but the answer is not correct. Anyone know why? Thanks!

Two thoughts (I did not check your number). Are you sing Webassign? You have tried with fewer decimals? And what did you use for the moment of inertia?

 

[FlipStyle1308]

Yes, I am using WebAssign. I have not tried with fewer decimals. For the moment of inertia, I used 0.04018...mr^2 = (0.82)(0.049)^2.

 

[nrqed]

Yes, I am using WebAssign. I have not tried with fewer decimals. For the moment of inertia, I used 0.04018...mr^2 = (0.82)(0.049)^2.

I am confused.. what is the 0.04018?

In any case, for a colid cylinder, I = 1/2 M R^2

 

[FlipStyle1308]

I never learned about that 1/2 thing. So (.5)(0.82)(0.049)^2 = 0.00098441

 

[nrqed]

I never learned about that 1/2 thing. So (.5)(0.82)(0.049)^2 = 0.00098441

yes.

Check in your book, you must have a list of moments of inertia for different objects around different axis of rotation. MR^2 works only for point masses or hollow cylinders.

 

[FlipStyle1308]

Oh okay, so I just solve RT/I, and I should get the answer...109.5072 rad/s^2?

 

[nrqed]

Oh okay, so I just solve RT/I, and I should get the answer...109.5072 rad/s^2?

? What did you use for R, T and I?
Oh.. Ithink you corrected it as i was posting,

That sounds right to me

 

[FlipStyle1308]

Okay cool!