A rock is thrown downwards from the edge of the Grand Canyon. With what velocity will it hit the donkey-riding tourist who is 40 m below?

Vf = 28 m/s

Explanation:

In order to find the final velocity of the rock, we will use the 3rd equation of motion. The third equation of motion for vertical direction is written as follows:

2gh = Vf² - Vi²

where,

g = acceleration due to gravity = 9.8 m/s²

h = height dropped = 40 m

Vf = final velocity of the rock = ?

Vi = Initial Velocity of the rock = 0 m/s (since, rock was initially at rest)

Therefore,

(2)(9.8 m/s²)(40 m) = Vf² - (0 m/s)²

Vf = √(784 m²/s²)

Vf = 28 m/s

tbh i dont know ether