How can a measured length be expressed?

Why do we need standard unit for measurement?

Define the term standard unit.

Define rest and motion.

State two precautions to be observed while measuring length with the help of a metre scale.

Name the types of motion in which a body moves along a straight path

Give an example of circular motion.

Give one example of linear motion.

Name the measuring device which can be used for measuring the girth of a tree.

How many centimetres are there in 1 m?

Why can hand span and arm length not be used as standard units of length?