The distance travelled by an object in time \( t \) is given by \( s = (2.5)t^{2} \). The instantaneous speed of the object at \( t = 5 \, \text{s} \) will be:
\( 12.5 \, \text{ms}^{-1} \)
\( 62.5 \, \text{ms}^{-1} \)
\( 25 \, \text{ms}^{-1} \)
\( 5 \, \text{ms}^{-1} \)