ayt2 . . . (ii) where, vx,vy is the initial speed of particle along X,Y-axes respectively, t be the time taken by the particle to reach maximum height. ∴‌‌sx=3t−‌
1
2
(1)t2 On differentiating both sides w.r.t t, we get ‌
dsx
dt
=3−t=vx′ where, vx′ is final speed of particle along X-axis. ∵ At maximum distance\/ height, speed becomes 0ms−1 ⇒‌‌t=3s ∴‌‌sx=3×3−‌
1
2
(1)×32 =9−‌
9
2
=‌
9
2
m sx=‌
9
2
∧
i
m and ‌‌sy=uyt−‌
1
2
ayt2 ⇒‌‌sy=0×3−‌
1
2
×‌
1
2
×32 =‌
−9
4
m ∴‌‌sy=−‌
9
4
(
∧
j
) ∵ Particle reaches to maximum height and returns. ∴‌‌sy=−‌