The rocket starts from rest at t=0 and travels straight up. Its height above the ground as a function of time can be approximated by s = bt? + ct3, where b and c are constants. At t=10 s, the rocket's velocity and acceleration are v3229 m/s and a=D28.2 m/s2. Determine the time at which the rocket reaches the supersonic speed (325 m/s). What is its altitude when that occurs?