What is the unit for force?

Aboxcar traveling at 12 m/s approaches a string of 5 identical boxcars sitting stationary on the track. the moving boxcar collides and links with the stationary cars and they all move off together along the track. what is the final speed of the cars immediately after the collision? (you may take the mass of each boxcar to be 18,537 kg.)

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity

How are series and parallel circuits simililar? both have multiple paths for electrons to travel. both require resistors in their circuits. both require a switch to complete the circuit. both have at least one path for electrons to travel.