Astate the importance of storage in energy systems. (2 marks) que.3b with suitable diagrams, describe the storage technologies. (6 marks) que.3c design a rotating mechanical flywheel from steel to supply 2 mwe of power for two minutes. you must specify the volume and radius, mass and maximum rotational speed. the density and maximum tensile strength of steel are 7.8g/em3 and 550mpa, respectively.

An electromagnetic wave with frequency 65.0 hz travels in aninsulating magnetic material that has dielectric constant 3.64 andrelative permeability 5.18 at this frequency. the electric fieldhas amplitude 7.20 \times 10^{ - 3} {\rm v}/{\rm m}. a. what is the speed of propagation of the wave? b.what is the wavelength of the wave? c.what is the amplitude of the magnetic field? d.what is the intensity of the wave?