Answer:
To meet the requirements of running for at least 30 minutes and developing a steady power of 500W, the flywheel engine needs to have sufficient energy storage capacity and be capable of delivering a steady power output.
Assuming that the flywheel engine is 100% efficient (i.e., no energy losses due to friction, air resistance, or other factors), the energy storage capacity required can be calculated as follows:
Energy storage capacity = Power x Time
= 500W x 30min
= 15,000 watt-minutes or 250 watt-hours
This means that the flywheel engine needs to be capable of storing at least 250 watt-hours of mechanical energy.