Two identical stones A and B are thrown vertically upward from the same point on level ground. Stone A is projected with speed u, whereas stone B is projected with speed 2u.
a. (i) Show that the maximum height reached by stone B is four times the maximum height reached by stone A.
b. (ii) If stone A rises to 12.5m, calculate the value of u. Take g=9.8ms−2.
c. (iii) Obtain the ratio of the time each stone spends ascending before coming momentarily to rest at its respective maximum height.