Question

f energy(E), momentum(P) and force(F) are chosen as fundamental units. the dimension of mass in new system is.
A.E^-1P^3
B.E^-1P^2
E^-2P^2
D.none of these.

Answer 1

You know : \[E_k = {{mv^2} \over 2}\]
\[v = {p \over m}\]
plug it in:
\[E = {{m ({p \over m})^2} \over {2}} = {{p^2} \over {2m}} \rightarrow m = {p^2 \over 2E}\]
the unit of 2 times E is still the same as the unit of E, thus (B) is the correct answer.

Answer 2

You do realise, that B lacks a factor of two, and more importantly both are the reciprocal of the correct expression that you derived.

Answer 3

Ooops, my bad. Please use the eqution editor when posting :) questions.

Answer 4

ok..