The force generated by a magnetic field B perpendicular to a wire carrying a current I is

where L is the length of the wire.
If we divide both sides for L, we get

where the ratio on the left is the force per meter of length, which is exactly what we want to find. So:
A.) 3,800
* Add 1800+2000 because they are both going forward, and you are look for the total amount of forward force. Hope this helped good luck!!!
Answer:

Explanation:
From the Law of Conservation of Momentum, we can write the following equation:

Because the toy car was initially at rest,
.
Therefore, we can plug in given values and solve for
:
(two significant figures).