Answer:
A. A resistor alters current and a switch turns current on and off
Explanation:
Resistor is the passive component that reduces the flow of current. Switch is the electrical device that turns on or off the current by closing and opening the electrical circuit.
Thus option A. A resistor alters current and a switch turns current on and off is correct.
(I assume that the 4 directions north-south-east-west are meant with respect to the wire seen from the top.)
We can use the right-hand rule to understand the direction of the magnetic field generated by the wire. The thumb follows the direction of the current in the wire (upward), while the other fingers give the direction of the field in every point around the wire. Seen from the top, the field has an anti-clockwise direction. Therefore, if we take a point at east with respect to the wire, in this point the field has direction south.
2 pounds because 2.0X1.5 m is 2 when rounded up
Answer:
Part a)

Part b)

Explanation:
As we know that two carts are moving in opposite directions
so here total momentum of two carts must be given by vector subtraction
It is given as



Now we know that total momentum of the system is conserved here as there is no external force on this system
so the speed of the first cart when second cart was at rest is given as



Direction because if you're moving in a circle the direction is constantly changing