The rigid body concept is important to understand position of an object. It can be defined as an object in which the distance between all molecules remains constant under the influence of any external force. It remains fixed at rest and does not change shape during motion also. Students can get answers to simple questions online on Tiwari Academy. Expert academicians provide important questions and answers for all chapters free of cost. Tiwari Academy is a learning platform suitable for children of all grades as they can download solutions for all subjects.