Dylan puts two magnetic toy trains very close to each other on a track. What will happen next, and -hy?
a
The trains will not move because the magnets are not touching.
b
The trains will move closer to each other because the magnetic force will pull the trains
together
с
The trains will move away from each other because the magnetic force will push the trains
apart.
d
The trains will move away from each other because the magnets are not touching.

What should the power status of a circuit be when measuring resistance with an ohmmeter?

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?