Question

An electric grinder uses a grinding wheel

Answer 1

 An electric grinder uses a grinding wheel of 12-cm radius.

Answer 2

(1500 rev/min)(min / 60 s) / (3.0 s) = 8.33 rev/s² 

(B) 
(1/2)(8.33 rev/s²)(3.0 s)² = 37.5 rev 

(C) 
(1500 rev/min)(min / 60 s)[2π(0.12 m) / rev] = 18.8 m/s