Posted by **Kayla** on Sunday, July 15, 2012 at 7:56pm.

A solid disk of 5kg and radius 0.5m turns at the rate of 10rpm. You then carefully place a 2kg book at the edge of table as it spins. What is the new rotation rate of the table(in rpm)?

- Physics (angular momentum) -
**Elena**, Monday, July 16, 2012 at 1:18am
I1 =MR²/2 =2•0.5²/2 =0.25 kg•m².

Assume the book is the3 point mass

I2=mR² =2•0.5²=0.5 kg•m².

The law of conservation of angular momentum

L1 = L2,

I1• ω1 =(I1+I2) •ω2,

I1• 2•π•f 1 =(I1+I2) • 2•π•f 2

f2= I1• f1/(I1+I2)=

=0.25•10/(0.25+0.5)=3.33 rpm

## Answer This Question

## Related Questions

- Physics - A woman with a mass of 50kg is standing on the rim of a large disk ...
- Physics - Someone please help me! I've been stuck on this problem for a while ...
- physics - A playground merry-go-round has a disk-shaped platform that rotates ...
- Physics - A solid disk with a mass ok 100 kg and radius of 0.2m turns clockwise ...
- Physics Please Help! - A solid disk with a mass ok 100 kg and radius of 0.2m ...
- Physics - A disk with a rotational inertia of 7 kgm^2 rotates like a merry-go-...
- Physics - A 2m radius uniform 50kg disk has an object of unknown moment of ...
- Physics - A rotating uniform-density disk of radius 0.7 m is mounted in the ...
- PHYSICS - A solid disk with a mass of 100kg and a radius of 0.2m, turns ...
- Physics - A solid disk with a mass of 100kg and a radius of 0.2m, turns ...

More Related Questions