Question

If unit of mass, length and time are tripled, then unit of energy becomes:

• A. $3$
• B. $\frac{1}{3}$
• C. $9$
• D. $\frac{1}{9}$

Answer 1

The correct option is A $3$

Unit of Energy $kg{m}^2/s^2$

Unit of length $=m$ (metre)

Unit of mass $=kg$ (kilogram)

Unit of time $=s$ (second)

Thus unit of energy in terms of unit of mass, length and time is given by,

$UnitofEnergy=\frac{\left(Unitofmass\right)\times (Unitoflength{)}^2}{(Unitoftime{)}^2}$

If the unit of mass, length and time are tripled the unit of energy will be,

$UnitofEnergy=\frac{(3\times Unitofmass)\times (3\times Unitoflength{)}^2}{(3\times Unitoftime{)}^2}$

$UnitofEnergy=3\times \frac{\left(Unitofmass\right)\times (Unitoflength{)}^2}{(Unitoftime{)}^2}$

$Unitofenergy=3\times Unitofenergy$

Therefore, if the unit of mass, length and time are tripled, the unit of energy will be, 3 times more than the original unit of energy.