Comments

@Truthcat, 9.8 is the change in velocity per second. The correct answer (assuming he ran straight out) is the square root of (7.4/4.9) or 1.23 seconds. So he'd need a horizontal velocity of 12.2 m/s (27.3 mph). If you assume he jumped up(and I can't imagine anybody not trying to jump up) at an average jump velocity of 1.5 m/s, then it takes 1.39 seconds to fall 7.4 meters, requiring a horizontal speed of 10.79 m/s, or 24.1 mpg. I assume the rock could jump a little faster than average, so required speed would be even less.

@Wallace R West, angular velocity has nothing to do with linearly moving objects. It only has to do with spinning objects like wheels and disks, also if I'm gunna get really accurate here, angular velocity isn't really a thing at all. It's a generalized term that people outside the engineering field use to describe the concept of linear and tangential velocity.

@occasionalmutant, an object one meter from the center has the same angular velocity as an object 10 meters from the center  they are both going through 90 degrees in one second. But the object further away has a faster linear velocity. The linear velocity is the distance from the center multiplied by the angular velicity

@Will I Am Shat nerd, I'm personally a fan of mixing 3 sets of classes together when I wanna blind people. I mix Fluids 2 (aerodynamics) with Heat Transfer/Thermodynamics, and then I hit em in the face with the upper level advanced dynamics and vibrations. If you add all the portions of those classes to cover all sides of a physics problem and the energy contained within the reactions, people lose their minds.

It seems like the entire picture is based in the measurement of the Rock as the baseline for the size of a pixel, but the rock is not standing straight up, he is hunched over during a jump. His height there might only be 5 ft 6 or 5 ft 4. That changes the measurements of the rest of this picture. The shot was also taken from below, possibly distorting the image. Gravity also doesn’t work the way this picture states. After 1 second he would only have fallen about 4.9 meters
I don't know if it makes a difference, but 9.8 isn't the rate of descent. It's the acceleration due to gravity, in m per second squared, but it would be approximately the same if the descent is only for about one second.