The question is incomplete. The complete question is :
A high-speed bullet train accelerates and decelerates at the rate of 4 ft/s^2. Its maximum cruising speed is 90 mi/h. What is the maximum distance the train can travel if it accelerates from rest until it reaches its cruising speed and then runs at that speed for 15 minutes?
Solution :
Given :
Speed of the bullet train, v = 90 mi/h
=
= 132 ft/s
Time = 15 minutes
= 15 x 60
= 900 s
Acceleration from rest,
Since, v(0) = 0, then C = 0, so velocity is
v(t) = 4t ft/s
Then find the position function,
It is at position 0 when t = 0, so C = 0, and the final position function for only the time it is accelerating is :
Time to get maximum cruising speed is :
4t = 132
t = 33 s
Distance travelled (at cruising speed) by speed to get the remaining distance travelled.
Total distance travelled, converting back to miles,
= 22.9125 mi
Therefore, the distance travelled is 22.9125 miles