# Block On Conical Surface

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http://img357.imageshack.us/img357/6476/80028206ag6.gif [Broken]

This question had me a little confused. I started by drawing a free body diagram of the block:

http://img246.imageshack.us/img246/9121/59804825wo9.gif [Broken]

Where W is the weight, N is the normal force and F is the friction force.

Because the cone is spinning, does that mean there will also be a frictional force in the direction extending out/into the page?

Since the block will effectively be moving in a circular path, its net acceleration will be given by:

$$\overrightarrow {\bf{a}} = r\alpha \underline {\widehat{\bf{t}}} + \omega ^2 r\widehat{\underline {\bf{n}} }$$

The question states that the angular acceleration increases very slowly? Can i approximate this to be zero?

Thanks in advance for any help.
Dan.

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