da answer is liquiddddddddd
Kinetic energy per unit of mass is

Given, 
Therefore,


Now potential energy per unit mass is

Given, 
Therefore,


Thus, total mechanical energy of the river water per unit mass is


OR

Answer: boyles law I’m pretty sure
8 meters per second. To find velocity is to divide distance by total time. so 400/50.
1) The coefficient of friction of the surface
2) The weight of that objects