The time that each car traveled.
Answer:

Step-by-step explanation:
The volume of the solid revolution is expressed as;

Given y = 2x²
y² = (2x²)²
y² = 4x⁴
Substitute into the formula
![V = \int\limits^2_0 {4\pi x^4} \, dx\\V =4\pi \int\limits^2_0 { x^4} \, dx\\V = 4 \pi [\frac{x^5}{5} ]\\](https://tex.z-dn.net/?f=V%20%3D%20%5Cint%5Climits%5E2_0%20%7B4%5Cpi%20x%5E4%7D%20%5C%2C%20dx%5C%5CV%20%3D4%5Cpi%20%5Cint%5Climits%5E2_0%20%7B%20x%5E4%7D%20%5C%2C%20dx%5C%5CV%20%3D%204%20%5Cpi%20%5B%5Cfrac%7Bx%5E5%7D%7B5%7D%20%5D%5C%5C)
Substituting the limits
![V = 4 \pi ([\frac{2^5}{5}] - [\frac{0^5}{5}])\\V = 4 \pi ([\frac{32}{5}] - 0)\\V = 128 \pi/5 units^3](https://tex.z-dn.net/?f=V%20%3D%204%20%5Cpi%20%28%5B%5Cfrac%7B2%5E5%7D%7B5%7D%5D%20-%20%5B%5Cfrac%7B0%5E5%7D%7B5%7D%5D%29%5C%5CV%20%3D%204%20%5Cpi%20%28%5B%5Cfrac%7B32%7D%7B5%7D%5D%20-%200%29%5C%5CV%20%3D%20128%20%5Cpi%2F5%20units%5E3)
Hence the volume of the solid is 
I don’t know the answer to this but I have an app called Socratic, it helps out with problems like this, download it and take a picture of what you are looking for, and it will give you the answers. I hope this helps..
you do not give a value for PI so I am using 3.14
V=PI x r^2 x H
you know volume and radius so put those into the equation
525 = PI (3.14) x 5^2 x H
525 = 3.14 x 25 x H
525 = 78.5 x H
divide both sides by 78.5
6.687 = H
round off answer as needed 6.7cm or 6.69cm
NOTE : the answer may vary slightly depending on the value of PI used.
but this is how you calculate the height.