Run electrity through or is postive to the circuit
If Fg=mg=ma and, Fg(planetX)=1/5Fg(earth)
then the time would be 5x of the time as gravity is acceleration. So 3.9s*5=19.5s
As the force of gravity is less, then the acceleration of masses is also less, therefore it will take more time for the object to fall by the factor of the force of gravity difference
Answer:
Density=mass/volume 40 divided by 8 =5