A drone launch system designed for emergency medical deliveries uses a vertical catapult. The drone is held in position on a launch pad, connected to three identical stretched elastic cables attached to a circular support rig.
Before the drone is launched, the extension of each of the three elastic cables is 7 m7\text{ m}7 m.
Each elastic cable behaves like an ideal spring with a spring constant of 120 N/m120\text{ N/m}120 N/m.
The total mass of the drone and its medical payload is 15 kg15\text{ kg}15 kg.
The gravitational field strength is g=9.8 N/kgg = 9.8\text{ N/kg}g=9.8 N/kg.
State the energy store that increases as the three elastic cables are stretched before launch.
Calculate the maximum height reached by the drone, assuming no energy is lost to the surroundings.
In reality, the actual maximum height reached by the drone is lower than this calculated value. Explain why, referencing energy stores and pathways.