Cognizant Software Developer interview questions

It wasn't very difficult.Iam a mechanical engineer and so i was questioned in technical side.simple questions like 1.function of differential,2.newton's three laws,3.kaizen,4.sixsigma,5.y cant petrol be used in diesel engine and vice versa,etc then HR questions like y choosing IT field being a mechanical engineer,tell me about yourself,then some questions related to what i told him.It seemed like a stress interview.but not very tough.

They were afraid of my experience and the technical skills that I brought. The interviewer felt insecure.