If a car crashes into another car like this, the wreck should go nowhere. Besides this being an unrealistic question, the physics of it would look like this:
Momentum before and after the collision is conserved.
Momentum before the collision:
p = m * v = 50000kg * 24m/s + 55000kg * 0m/s = 50000kg * 24m/s
Momentum after the collision:
p = m * v = (50000kg + 55000kg) * v
Setting both momenta equal:
50000kg * 24m/s = (50000kg + 55000kg) * v
Solving for the velocity v:
v = 50000kg * 24m/s/(50000kg + 55000kg) = 11,43m/s
Steam powered boats run from an engine, using power, gears, and cranks to function.
Sailboats use no engine and rely on winds to move and change the direction of the boat.
Well, one example is that the weight of the rider puts downward force on the motorcycle, which is absorbed by the suspension or shocks or something.
For the work-energy theorem, the work needed to stop the bus is equal to its variation of kinetic energy:

where
W is the work
Kf is the final kinetic energy of the bus
Ki is the initial kinetic energy of the bus
Since the bus comes at rest, its final kinetic energy is zero:

, so the work done by the brakes to stop the bus is

And the work done is negative, because the force applied by the brake is in the opposite direction to that of the bus motion.