Choose the correct answer
I) On a practical day, Akbar and Raventh were measuring distances between two places. Akbar is using an inch scale while Raventh is using a feet scale. After submission, the teacher asked both of them to convert the answers in a familiar system. Which system do they need to follow?
II) We know the elevators which are used in tall buildings. Imagine an elevator always on the ground floor when not in use. Some people used it sometimes. Anyway at the end it will again come to the ground floor. Now, which of the following is zero during 3 complete ups and downs?