[12 piece bucket]

"Thrust is an acceleration force" (2-M-1)

Imagine you have four engines on a boat- Engine 1, 2, 3, and 4. Each one has only so much gas in it so they are just going to be able to maintain their thrust for a certain period of time- say one minute. If you want high acceleration you could run all four together from the start- but you better make sure that the race is short enough so you don't run out of gas before the finish line.

Imagine you have the same boat- and let's assume no friction. First you let engine number 1 accelerate the boat until just before it runs out of gas, now you hit engine #2 and do the same , then engine3 then engine 4- that's how you get maximum velocity.

Measured by time based on when the engine kicks in
Determined and Adjusted by the operator

Good post . . . When did you steal a boat?