(adsbygoogle = window.adsbygoogle || []).push({}); Flywheel Question??

Hi all I have done the following question:

A flywheel , intially rotating at a speed of 600 rev/min, is brought to rest with uniform angular deceleration in 10 seconds.

A) How many revolutions does the flywheel make before coming to rest?

I used Pheta = (Wo + W)t/2 to get 314.16 rads. The I used 314.16/2Pi to get 50 revolutions

B)Determine the magnitude and direction of the resultant linear acceleration of a point A on the flywheel 0.5seconds before coming to rest. Assume the point A is positioned at a fixed radius of 150mm from the axis of rotation.

I firstly worked out angular acceleration to be -6.2832 rads/sec. I then found W to be 3.14 rads/sec. Using the formula for radial acceleration (ar) = w^2r I got 1.4804.

And for tangential acceleration i got -0.94248. Therefore the resultant linear acceleration using pythagorus is 1.755. The resultant angle is tan-1(-0.94/1.48) = -32.48 degrees.

Now whats confusing me is all the minus signs. Is this a legit answer??? The minus angle is confusing me?

The final question is:

C) Draw a vector diagram showing the maginitude and direction of the resultant linear acceleration and its radial and tangential components??

Shall I draw the vector diagram using the answers above. So it will end up being in the 3rd quadrant????

Cheers

Do I just use the minus values worked out above.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Flywheel Question?

**Physics Forums | Science Articles, Homework Help, Discussion**