mass is measured by physical balanced where weight is measured by spring balance. Explain.

What is a spring balance?

What is measurement of a physical quantity?

Explain 'balanced diet'.

Name the physical quantity which is measured in weber ampere^(-1) .

Potential of a spring is measured in ……………

Which type of mass of a body is measured by a physical balance?

Precise measurements of physical quantities are a need of science. For example, to ascertain the speed of an aircraft, one must have an accurate method to find its positions at closely separated instants of time. This was the actual motivation behind the discovery of radar in World War II. Think of different examples in modern science where precise measurements of length, time, mass etc. are needed. Also, wherever you can, give a quantitative idea of the precision needed.