Question

The unit of length, velocity and force are doubled. Which of the following is the correct change in the other units?

• A. Unit of time is doubled
• B. Unit of mass is doubled
• C. Unit of momentum is doubled
• D. Unit of energy is doubled

Answer 1

The correct option is A Unit of time is doubled

The dimensions of velocity are $L{T}^{-1}$.

Since the length is doubled then in velocity there must not be any change in the time in order to make it double.

The dimensions of force are $ML{T}^{-2}$.

Since the time cannot be doubled and the length is already doubled, in order to double the force the mass will get doubled

The dimensions of momentum are $ML{T}^{-1}$.

As the time and mass are constant and length is doubled so, the momentum will get doubled.

The dimensions of energy are $M{L}^2{T}^{-2}$.

As the time and mass are constant and length is doubled so, the energy will become four times.