I’m sure the answer is correct and it is below
“ A catapult works because energy can be converted from one type to another and transferred from one object to another. ... This energy is stored in the launching device as potential, or stored, energy. The catapult you are about to make uses elastic potential energy stored in a wooden stick as you bend it.”
Answer:

Explanation:
We have to combine the following formula to find the mass yield:


The diffusion coefficient : 
The area : 
Time : 
ΔC: 
Δx: 
Now substitute the values

![M=-(6.0*10^{-8} m/s^{2})(0.25 m^{2})(3600 s/h)[(0.64-3.0kg/m^{3})(3.1*10^{-3}m)]](https://tex.z-dn.net/?f=M%3D-%286.0%2A10%5E%7B-8%7D%20m%2Fs%5E%7B2%7D%29%280.25%20m%5E%7B2%7D%29%283600%20s%2Fh%29%5B%280.64-3.0kg%2Fm%5E%7B3%7D%29%283.1%2A10%5E%7B-3%7Dm%29%5D)

Explanation:
the owner of the bridge and some workers
Answer:
The surface area of the primary settling tank is 0.0095 m^2.
The effective theoretical detention time is 0.05 s.
Explanation:
The surface area of the tank is calculated by dividing the volumetric flow rate by the overflow rate.
Volumetric flow rate = 0.570 m^3/s
Overflow rate = 60 m/s
Surface area = 0.570 m^3/s ÷ 60 m/s = 0.0095 m^2
Detention time is calculated by dividing the volume of the tank by the its volumetric flow rate
Volume of the tank = surface area × depth = 0.0095 m^2 × 3 m = 0.0285 m^3
Detention time = 0.0285 m^3 ÷ 0.570 m^3/s = 0.05 s