A gymnast leaves a trampoline moving vertically upwards and reaches a highest point 1.35 m above the take-off position. Measurements show that the increase in the gymnast's gravitational energy store is 90% of the energy initially in the gymnast's kinetic store. Use g=10 N/kgg=10\ \mathrm{N/kg}g=10 N/kg.
What is the speed of the gymnast on leaving the trampoline?
5.5 m/s5.5\ \mathrm{m/s}5.5 m/s
5.2 m/s5.2\ \mathrm{m/s}5.2 m/s
16.4 m/s16.4\ \mathrm{m/s}16.4 m/s
5.8 m/s5.8\ \mathrm{m/s}5.8 m/s