Question 6483
in terms of maths we have T {{{alpha}}} {{{a^3/sqrt(d)}}} or converting to an equation, 


{{{T = ka^3/sqrt(d)}}} where k is the constant of proportionality.


So, now we need to find the value of k. For this we need to know T, a and d --> which we do from the question. So put the values into the equation to find k:


{{{4 = k2^3/sqrt(9)}}}
{{{4 = 8k/3}}}
{{{4*3/8 = k}}}


--> k = {{{3/2}}}


so the equation is now: {{{T = 3a^3/2sqrt(d)}}}


And now we have it, we can do the final part: "find T when a=-1 and d=4"


{{{T = 3(-1)^3/2sqrt(4)}}}
{{{T = 3(-1)/(2*2)}}}
{{{T = -3/4}}}


jon.