Gears essentially allow between teeth so high forces can be
     Gears essentially allow  between teeth so high forces can be transmitted while still undergoing essentially rolling contact.  Positive engagement  Interference fit  Frictional engagement  A and B  in structural steels that behave in a completely ductile manner during ordinary lab strength tests is a big concern for Engineers and Metallurgists.  Plastic failure.  Stress concentration.  Brittle failure.  All of the above. 
  
  Solution
Answers:
1. A
2.A

