Answer:
If by 1.5 MJ you mean 1.5E6 Joules then
W = P t = power X time
W / t = P power
P = 1.5E6 J / 600 sec = 2500 J / s
P = I V
a) I = 2500 J/s / (240 J/c) = 10.4 C / sec = 10.4 amps
b) Q = I t = 10.4 C / sec * 300 sec = 3120 Coulombs
c) E = P * t = 2500 J / sec * 100 hr * 3600 sec / hr = 9.0E8 Joules
The potential energy of a 30N ball on the ground will be zero. With respect to height, h. Potential energy will be calculated like this. P=mgh. So if its on the ground relatively speaking the h=0. Thus inputting into the above formula. P=0.
It would be a bike that doesn't use an electric circuit.