A dragster races down a 400 m strip in 8 seconds. Its distance, in metres, from the starting line after t seconds is s(t)=6t^2+2t

a) find the dragster's velocity and acceleration as it cross the finish line.

b) how fast was it moving 60 m down the strip?

I need help with part b.. I thought that i would use the acceleration formula i made up in part a but it did not work out since the a(t) formula in part a is a constant number > 12

Help with part b. thanks