Divers in acapulco dive from a cliff that is 63 m high. if the rocks below the cliff extend outward for 21 m, what is the minimum horizontal velocity a diver must have to clear the rocks?

Explanation:

Consider the vertical motion of diver.

We have equation of motion s = ut + 0.5 at²

        Initial velocity, u = 0 m/s

        Acceleration, a = 9.81 m/s²  

        Displacement, s = 63 m      

     Substituting

                      s = ut + 0.5 at²

                      63 = 0 x t + 0.5 x 9.81 x t²

                      t = 3.58 s

Now consider the horizontal motion of diver.

We have equation of motion s = ut + 0.5 at²

        Displacement, s = 21 m

        Acceleration, a = 0 m/s²  

        Time, t = 3.58 s      

     Substituting

                      s = ut + 0.5 at²

                      21 = u x 3.58 + 0.5 x 0 x 3.58²

                     u = 5.86 m/s

Minimum horizontal velocity a diver must have to clear the rocks is 5.86 m/s

it has to be b, about 97 percent.