The initial horizontal velocity of the rock, in m/s is 21.241 m/s.
<h3>What is projectile?</h3>
When an object is thrown at an angle from the horizontal direction, the object is said to be in projectile motion. The object which follows the projectile motion.
Time taken by the stone to reach the ground is
t = √2h/g
t = √(2x 86)/9.81
t = 4.19s
The horizontal velocity is
V(x) = Horizontal distance traveled / Time taken t
Put the values, we get
V(x) = 89 m/4.19 s
V(x) = 21.241 m/s
Thus, the horizontal velocity is 21.241 m/s
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