Can a Flywheel Efficiently Power a Low-Pollution Car for Long Distances?

[LBloom]

Homework Statement

"One possibility for a low-pollution automobile is for it to use energy stored in a heavy rotating flywheel. Suppose such a car has a total mass of 1400 kg, uses a uniform cylindrical flywheel of diameter 1.90 m and mass 210 kg, and should be able to travel 330 km without needing a flywheel "spinup."

a)Make reasonable assumptions (average frictional retarding force = 500 N, twenty acceleration periods from rest to 93 km/h, equal uphill and downhill, and that energy can be put back into the flywheel as the car goes downhill), and estimate what total energy needs to be stored in the flywheel.
b)What is the angular velocity of the flywheel when it has a full "energy charge"?
c)About how long would it take a 150-\rm hp motor to give the flywheel a full energy charge before a trip?

Homework Equations

K_fw=1/2*I*[tex]\omega[/tex]^2
I=1/2*M_fw*R^2
Frictional Work: W=F_fd

The Attempt at a Solution

I converted the km/h to m/s, to get that the car maxes out at (155/6) m/s
I converted km to m, to get that the total trip was 330000m

I found that I=94.7625 and that the W_f=1.65*10^8
I assume that I calculate the acceleration to find the average velocity for the entire trip, although I'm not quite sure how to do that yet, but I'll get started on that. Honestly, I'm just confused what the significance of the fact that there are 20 acceleration periods. Could I divide the trip in 20, and figure out the work required for that distance and multiply it by 20, or is that unneeded?

Edit: I think I found the average velocity of the trip to be 12.9167 m/s. Can anyone tell me if I'm right or on the right track?

 

[Nate810]

Edit: So I think I figured out the acceleration. I took the difference between the max velocity and the average velocity and divided it by 20, to get that the acceleration was 0.443 m/s^2. Does this sound right?

 

[tomcue]

I would like to comment on the use of a flywheel as a potential energy storage system for a low-pollution automobile. While it is true that flywheels can store large amounts of energy and can be used to power a vehicle without using fossil fuels, there are some limitations and challenges that need to be considered.

Firstly, the use of a flywheel in a car would require a significant amount of space and weight, as seen in the given scenario where the flywheel itself has a mass of 210 kg. This added weight and space could potentially affect the overall performance and efficiency of the car.

Secondly, the flywheel system would require a complex mechanism to transfer the energy from the flywheel to the wheels of the car, which can add to the cost and maintenance of the vehicle.

Additionally, the assumption that energy can be put back into the flywheel as the car goes downhill may not be realistic in real-world driving conditions. There may be situations where the car is not able to capture or store this energy, leading to a loss of efficiency.

In conclusion, while the idea of using a flywheel as an energy storage system for a low-pollution automobile is intriguing, further research and development is needed to address these limitations and make it a viable option for commercial use.