$a\ =\ \frac{2d}{t^2}$  

 $a\ =\ 2dt^2$  

 $a\ =\ 2d\ -\ t^2$  

none of the above

 $h\ =\ PE\ +\ mg$  

 $h\ =\ \frac{PE}{mg}$  

 $h\ =\ \frac{mg}{PE}$  

 $h\ =\ PE\ -\ mg$  

 $a\ =\ \frac{t}{\left(v_{f\ }-\ v_i\right)}$  

 $a=\frac{vf}{v_{i\ }}-t$  

 $a=\ \frac{\left(v_{f\ }-v_i\right)}{t}$  

none of the above

 $r\ =\ \frac{a}{v^2}$  

 $r\ =\ v^2r$  

 $r\ =\ \frac{v^2}{a}$  

 $r\ =\ a\ -\ v^2$  

 $m_{2\ }=\ d^2FGm_1$  

 $m_{2\ }=\ \frac{dF^2}{Gm1}$  

 $m_{2\ }=\ \frac{d^2F}{Gm_1}$  

 $m_{2\ }=\ \frac{Gm_1}{d^2}$  

 $t\ =\ \sqrt{\frac{2d}{a}}$  

 $t=\ 2d^2\ -\ a$  

 $t\ =\ \sqrt{\frac{a}{2d}}$  

 $t\ =\ \sqrt{2da}$  

 $I\ =\ \frac{P}{R^2}$  

 $I\ =\ \sqrt{\frac{R}{P}}$  

 $I\ =\ \sqrt{\frac{P}{R}}$  

None of the above

 $r\ =\ \sqrt{\frac{\pi h}{2v^{ }}}$  

 $r\ =\ \sqrt{2v\pi h}$  

 $r\ =\ \sqrt{\frac{2v}{\pi h}}$  

None of the above

 $a\ =\ \frac{\left(d-\frac{1}{2\ }vt^2\right)}{t}$  

 $a\ =\ \frac{2\left(d-vt\right)}{t^2}$  

 $a\ =\ \frac{\left(d\ -\ vt\right)}{2\ }t^2$  

none of the above