huh??
Forgive me, if I am wrong but from the tone of your question I assume that you are still at school and want to be a pilot some day.
In very broad terms your pilot won't want to takeoff unless at the critical moment if he has to stop, he can do so safely. Which is why aircraft lift off well before the end of the runway on normal flights. In fact, still very broadly speaking, on a cool dry day a worst scenario emergency stop successfully accomplished might only use up 60% of the runway. At its top weight the aircraft might accelerate at 4.5ft/sec/sec and decelerate at 9ft/sec/sec but there are many factors that contribute to the actual figure. Let's stick with that and assume that a lightly laden aircraft will perform 50% better. So it accelerates at 6.75ft/sec/sec.
In that case it takes about 13 secs to reach 60mph, about 22 secs to reach 100mph and about 35 secs to reach 160mph.
You appreciate these are very rough figures indeed.
Whatever your purpose in asking, Good Luck. A lot of my passengers have asked the same sort of thing and I hope you get a great deal of pleasure when it happens to you for the first time too.
Best Rgds
enicalyth