Answer:
Your clue is impossible, water release at a velocity of 20m/s cannot lift a 10 kg garbage can under earth's gravity.
F=lambda 2v^2 (assuming elastic collision)
= 2mv^2/d
= 2(dm/dt)(v^2)/u
= 20N
which can lift a can of 20/9.81 kg
so your water can only lift a max of 2.04 kg garbage can.
Explanation: