If I have a solid disc with a diameter of 30 cm and a mass of 700 grams with a speed of 45 rpm, and a mass of 350 grams falls 6 cm from center what is the speed of the disc. There are also no external torques.(adsbygoogle = window.adsbygoogle || []).push({});

I have no problem solving the angular momentum of the disc before the mass falls on it.

L=Iబ which is L=1/2(.7 *.15^2)*4.9

L=3.85*10^-2

From there I do not know how to incorporate the 350 grams or the 6 cm into the problem.

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

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: Conservation of momentum

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