Question 376391
{{{f = kq^2h}}}, where k is a constant of proportionality.  Now from the given,
{{{54 = k*3^2*2}}}, or {{{54  = 18k}}}, or k = 3, so that the working equation is {{{f = 3q^2h}}}.  When q = 4 and h = 5, {{{f = 3*4^2*5 = 240}}}.