see if you can solve this equation...?

Question

if u=0.25, t=3.5 and a=-0.05

then what is s in the following equation: s=ut 1/2 at"
("=squared)

Answer 1

1st stone:
u1 = 0m/s
v1 = v1
a1 = 9.8
s1 = s
t1 = t

2nd stone:
u2 = 0
v2 = v2
a2 = 9.8
s2 = s
t2 = t -1 ( as it took one second less to fall)

As s1 = s2 let:

u1t1 + 1/2a1t1^2 = u2t1 + 1/2a2t2^2
1/2 x 9.8 x t^2 = 14 (t - 1) + 1/2 x 9.8 x (t - 1)^2
4.9t^2 = 14t - 14 + 1/2 x 9.8 x (t^2 + 2t - 1)
4.9t^2 = 14t - 14 + 4.9t^2 - 9.8t + 4.9
0 = 4.2t - 9.1
t = 2.17s

then we can take

1st stone:
u1 = 0m/s
v1 = v1
a1 = 9.8
s1 = s
t1 = 2.17

s = ut + 1/2at^2
s = 1/2 x 9.8 x (2.17)^2
s = 23.1 m

Answer 2

.25 * 3.5 = .875 * .5 = .21875 * t^2
t^2 = 12.25 * .21875 = 2.6796675

Answer 3

.0765625