Why does a spring balance show wrong measure after long use?

Why do spring balances show wrong reading after long use ?

What does spring balance measure : Mass or Weight?

Why are the bridges declared unsafe after long use ?

Why does a dry cell become dead after a long time even if it has not been used?

A LASER is a source- of very intense, monochromatic, and unidirectional beam of light. These properties of a laser light can be exploited to measure long distances. The distance of the Moon from the Earth has been already determined very precisely using a laser as a source 'of light. A laser light beamed at the Moon takes 2.56 s to return after reflection at the Moon’s surface. How much is the radius of the lunar orbit around the Earth?

Give reason why does a dry cell become dead after long time even if has not been used?

A player throws a bail upwards with an initial speed of 29.4 m s^-1 . To what height does the ball rise and after how long does the ball return to the player’s hands? (Take g = 9.8 m s-2 and. neglect air resistance).

Why does a dentist use a concave mirror?

Why does Nitrogen show catenation properties less than phosphorus?

Why fluorine does not show disproportion reaction?