Question

EJ is taking his little sister, Ebony, on her first carousel ride. His mass is 75.0 kg, and her mass is 10.0 kg. They ride the same horse, and it is 11.0 meters from the center of the carousel. If their angular momentum is 14020 kg m2/s, what is their speed?
Remember to identify all data (givens and unknowns), list equations used, show all your work, and include units and the proper number of significant digits to receive full credit.

Answer 1

You have to find interia using I=mr^2.  

m=75+10  

radius = 11  

Then you have to substitute in first formula above to find the angular speed.

14020=(75+10)x v x 11  

v= 14020/ (85x11) = 15m/s

To find linear speed, use V=wr.

Equation: V = 11*1.363 = 15m/s = 33.6mi/hr

Hope this helps! :)