Verified answer

Time to fall vertically is independent of horizontal velocity.

Time to fall vertically = sqrt. (2h/g), = sqrt. (64/9.8), = 2.5 secs. approx.

To cover a horizontal distance of 25m. in the same time, (25/2.5) = 10m/sec., approx.

let's suppose the whole process takes time t .as rock covers 32 vertically in time t.

therefore applying s=ut + 0.5gt^2 as u= 0(for vertical)

s=0.5gt^2

32=0.5*10*t^2

we get t=sqrt(32/5)=2.53sec

now ball covers 25m horizontally and also it has no acc in tht direction so applying

s=ut

25=u*2.53

or

u=25/2.53=9.8=10m/s approx . and why the way jada is a powerful man.......gd lk

First find the time it took for the rock to hit the water. In the y direction, you know distance (dy), acceleration (a) (g), and initial velocity (vi) (0 m/s).

dy=vi*t+at^2/2 (vi=0)

sqrt(2*dy/a)=t

Now, you can apply that equation again in the x direction, where a=0. (distance in the x direction is dx).

dx=vi*t

dx/t=vi

dx/sqrt(2*dy/a)=vi

Plug in the numbers.

25 m/sqrt(2*32 m/9.8 m/s^2)=9.78 m/s or around 10 m/s