Question
Out of the following pair, which one does NOT have identical dimensions is-
A.
impulse and momentum
B.
angular momentum and planck’s constant
C.
work and torque
D.
moment of inertia and moment of a force (towards north-west)
Answer :
moment of inertia and moment of a force (towards north-west)
Solution :
$$\eqalign{
& {\text{Moment of Inertia,}}\,\,I = M{r^2} \cr
& \left[ I \right] = \left[ {M{L^2}} \right] \cr
& {\text{Moment of force,}}\,\,\,\overrightarrow \tau = \overrightarrow r \times \overrightarrow F \cr
& \left[ {\overrightarrow \tau } \right] = \left[ L \right]\left[ {ML{T^{ - 2}}} \right] = \left[ {M{L^2}{T^{ - 2}}} \right] \cr} $$