## anonymous 5 years ago 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.

1. anonymous

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.

2. anonymous

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

3. anonymous

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

4. anonymous

ok..