There are 2 problems, very alike, that I don't know exactly what to do about. I think I may be missing some information that I should know before trying such problems. Any help would be very appreciated. 1. The problem statement, all variables and given/known data The first: A particle P starts at the point O and travels in a straight line. At time t seconds after leaving O the velocity of P is vm s−1, where v = 0.75t^2 − 0.0625t^3. Find (i) the positive value of t for which the acceleration is zero, (ii) the distance travelled by P before it changes its direction of motion. The second: A particle P moves in a straight line, starting from the point O with velocity 2 ms−1. The acceleration of P at time ts after leaving O is 2t^(2/3) m s−2. (i) Show that t^(3/4) = 5/6 when the velocity of P is 3 m s−1. (ii) Find the distance of P from O when the velocity of P is 3 m s−1. 2. Relevant equations All the suvat equations, probably, should be relevant. 3. The attempt at a solution For the first, we can maybe put a 0 for the a in a = delta v/delta t?